Category Archives: Batteries

What is an Instantly Rechargeable Battery?

The batteries required to power them have so far impeded advancement of electric cars. A primary difference between vehicles powered by fossil fuels and those powered by batteries is that batteries tend to discharge with use and require a finite time to recharge, immobilizing the vehicle for that period. On the other hand, simply filling up the gas-tank with fossil fuel is enough to keep the car rolling on the road. However, that may be changing now.

Research at the Purdue University has led to the development of a new type of battery that can be recharged instantly. The new battery is also affordable, safe, and environmentally friendly. Presently, the viability of electric vehicles hinges on the availability of charging ports in convenient locations. However, the new battery technology allows drivers of hybrid and electric vehicles to charge up very quickly and easily similar to what the drivers of conventional cars do at a gas station.

This breakthrough will definitely boost the switching to electric cars. Not only does the new technology make it more convenient to drive electric cars, but it also reduces substantially the total infrastructure necessary for charging electric cars. Researchers, both professors and doctoral students, from the Purdue University have co-founded IF-Battery LLC for developing and commercializing the technology.

The new battery is a flow type and does not require to be charged at an electric charging station—it is enough to replace the fluid electrolyte of the battery. This is very similar to filling up the gas tank. The fluids from the spent battery can be collected and recharged at any hydroelectric, wind, or solar plant. Therefore, when an electric car using this new battery arrives at the refueling station, the driver can simply deposit the spent fluids for recharging, while filling up his or her battery with new fluids just as he or she might fill gas in a traditional car.

The difference between this flow battery and those developed earlier so far is this new battery does not have any membrane. The membranes other flow batteries use are expensive and vulnerable to fouling. Not only does membrane-fouling limit the number of recharge cycles of the battery, but can also contribute to a fire. Components used in the IF-Battery are safe to store in a family home, and are stable enough so major production and distribution centers can use them, and are cost effective.

In place of building several charging stations, it would be far simpler to transition the existing gas-station infrastructure for accommodating cars using the new battery system. As the battery chemicals are very safe, existing pumps could even be used to dispense these chemicals.

Although sale of electric and hybrid vehicles are growing worldwide, industry and consumers alike are facing the challenge of extending the life and charge of the battery and the infrastructure necessary to charge the vehicle.

At this time, the researchers need more time to complete their research before they can bring the technology to regular use. The researchers are trying to draw interest from investors and working towards publicizing their innovation.

Battery Monitoring with Comparators

So many portable consumer electronics gadgets in use today use small, button- or coin-cell batteries. Sometimes it is necessary to monitor their state-of-charge (SOC) and health efficiently without affecting their SOC significantly, but this can be a challenge. However, simple low-power monitoring circuits for small batteries using comparators can overcome this challenge.

Managing Batteries in Portable Systems

Usually, the system engineer budgets the system power requirements carefully during the system design. A micro-controller or microprocessor within the gadget is the actual brains that manages the system reliably and performs the required functions. Since it is typical for the controller to be power-hungry, as it is the workhorse of the system, there is not much sense in making the controller do all the work. To prevent unnecessary power dissipation, the controller is designed to remain asleep for extended periods, only waking up when flags are presented on the GPI pins.

Therefore, engineers resort to using low-power circuits for continually monitoring the vital functions of the system. When these circuits detect an event, they flag the micro, usually in the form of interrupts. The micro then wakes up to perform its required duty. One of the vital functions of such circuits is to monitor the state of the battery. When the battery voltage dips below the pre-defined threshold, it means it has discharged and requires charging. Likewise, as soon as the battery voltage crosses another pre-defined threshold, it means it is completely charged with no further requirement of further charging. Similarly, it is important to monitor the case temperature of the battery and the ambient temperature, as this provides much information about the loading conditions on the battery, and the presence of a fault.

Using Comparators for Monitoring

Although there are sophisticated battery monitors with fuel gauges, and monitoring battery voltage and temperature with an analog-to-digital converter is possible, these essentially require careful tradeoffs with portable gadgets. A designer must consider form factor, cost, accuracy, speed, and power consumption when creating the design, as different systems may have different priorities.

It is possible to have a simple comparator monitoring the voltage at the battery terminals. For a fully charged battery, the output voltage of the comparator transitions from high to low and from low to high for indicating a fully discharged battery. When implemented with external hysteresis, thresholds can be pre-defined to yield the proper output states.

The comparators can be tiny-footprint devices with internal references, consuming very low quiescent currents. When large-value resistors are used in the circuit, the overall operating current will be comparable to the typical self-discharge rate of the battery. By designing the circuit to operate from a low supply voltage of about 1.7 V and consuming less than 2 µA of current, the circuit will be able to produce the proper output state even when the battery has only a minimum charge remaining.

The component values necessary to realize the application for battery state monitoring must be selected with care. The determined threshold value should provide a narrow band of hysteresis to allow for more cushion for component variation and tolerances. Using resistors with 0.5% makes the circuit work with ±1% accuracy.

Boosting Battery Life in IoT Devices

Earlier, the assumption was unused energy from the environment, machines, people, and so on could be used to power valuable devices and this would be done for free. The assumption was based on the convergence of four key technologies to enable mass adoption of energy harvesting—efficient voltage converters, efficient harvesting devices, low-power sensors, and low-power microcontrollers. However, it was soon realized that although energy harvesting does operate for free, the system needs investment, which is not free. That has led to the thinking that perhaps energy harvesting may not be the right technology for powering smart energy applications.

Now, with the growth of IoT devices, more sophisticated sensors, more pervasive connectivity, and secure, low-power microcontrollers, there are more devices to be powered than ever before. With most devices being small and battery powered, design engineers are facing challenges such as energy efficiency and long battery life.

In reality, it is no longer worthwhile using sensors for measuring and analyzing the energy consumption of individual light bulbs, since the cost of such a system would be more compared to the energy cost to run the lamp. In addition, there are numerous low-energy-consuming light sources available.

Development of engineering systems now place more emphasis on maximizing performance and saving energy. This is because most IoT devices spend a significant part of their life sleeping or hibernating, where the part is neither operating nor completely shut down. In this state, the device is actually drawing quiescent current, and this places the maximum impact on battery life, as it contributes to the standby power consumption of the system.

The development of nanoPower technology has led to great advancements in maximizing performance and saving energy. Newer products, with advanced analog CMOS process technology, now operate in their quiescent state with nanoampere currents that are almost immeasurable. The trick in maximizing energy-saving benefits from these products is first by duty-cycling them, and secondly by decentralizing the power-consuming architecture.

Benefits of nanoPower technology also extend to their ability to turn off circuits within the system. For instance, the nanoPower architecture may allow powering critical components such as real-time clocks and battery monitoring, while cutting off power to major consumers such as the RF circuits and the microcontroller, which can either turn off or enter their lowest power-consumption mode.

System monitoring ICs play a huge role here with their small packages and nanoamp quiescent current levels. Comparators, op amps, current sense amplifiers, and more help ensure important issues such as the voltage levels on microcontrollers are at proper levels. For instance, a nanoPower window comparator monitors the battery voltage and provides an alert if the battery voltage goes beyond allowable levels. Apart from being a valuable safety function, this also helps to extend the battery life, as the microcontroller need not operate until it has received an alarm from the comparator.

Another power-saving scheme is OR-ing the battery supply with voltage from a wall wart or an additional battery, using OR-ing diodes. These are Schottky diodes in series with the battery supply for limiting the voltage drop. For instance, MAX402000 diodes can save tens to hundreds of milliWatts of battery power when used in a smart way.

Salt Water Makes Li-Ion Batteries Safer

So far, high-energy lithium-ion batteries were always a matter of concern on account of safety. If you wanted to remain safe from exploding batteries, an aqueous battery such as made from nickel/metal hydride would be preferable, but then it would give you lower energy.

Usually, 3-V batteries using aqueous electrolyte technologies are unable to achieve higher voltages because of the cathodic challenge. This happens as the aqueous solution degrades one end of the battery made from either lithium or graphite. One research team solved this problem by covering the graphite or lithium anode with a gel polymer electrolyte coating.

As the coating is hydrophobic, it does not allow water molecules to reach the electrode. However, when the battery charges for the first time, the coating decomposes, forming a stable layer separating the solid anode from the liquid electrolyte. The layer protects the anode from side reactions that could deactivate the anode. This allows the battery to use anode materials that are more effective, such as lithium metal or graphite, and allowing the battery reach higher energy densities and cycling abilities. The gel coating improves the safety of the battery, and is now comparable to the safety standards of non-aqueous lithium-ion batteries.

Organic solvents used in non-aqueous batteries are highly flammable. In comparison, aqueous lithium-ion batteries use water-based electrolytes that are non-flammable. Another advantage of this gel polymer coating is if this layer is damaged, the reaction with the lithiated graphite or lithium anode is very slow, preventing smoking, fire, or explosion that would normally happen if in the damaged battery the metal came into direct contact with the electrolyte.

This aqueous lithium-ion battery with the gel covering the anode has power and energy density matching its counterpart with non-aqueous electrolyte, and is suitable for commercial applications. However, the researchers intend to improve on the number of full-performance cycles the battery can complete. According to the researchers, this will reduce material expenses as far as possible. Although at present the battery is able to complete only 50-100 cycles, the team intends to increase that to 500 or more.

The researchers are also trying to manipulate the electrochemical process to allow the battery achieve 4 V on its terminals. According to the researchers, this is the first time they have been able to stabilize the reactive anodes such as lithium and graphite in aqueous media. They feel this opens a huge field of possibilities into several different topics in electrochemistry. For instance, this could cover not only lithium-ion batteries, but also lithium-sulfur, sodium-ion batteries, and other batteries using multiple ion chemistry technologies such as magnesium and zinc, and electrochemical and electroplating synthesis.

The researchers understand that interphase chemistry requires to be perfected before they can commercialize their product. They also feel that they need to work more towards scaling up the technology so that big cells can be used for testing. However, the researchers are confident they will be able to commercialize their product within the next five years, provided they are able to gather more funding.

A Cheaper Alternative for Batteries—Sodium Ion

A vast majority of electronic equipment running on batteries rely on the Lithium-ion technology for their electrode material. Since Lithium is relatively rare, its mining and refining make it an expensive material to use. This has led scientists to search for a cheaper alternative, and they have turned to the cheapest substance available, the common salt. A team from Stanford has developed a battery based on Sodium-ion whose cost per storage capacity is far lower than that of the existing batteries based on Lithium-ion.

Salt, being nearly omni-present in our oceans, together with its ability to carry charge, is a near-perfect candidate for low-cost energy storage. Many forms of Sodium-based batteries are now available, some with a unique design of anode made from a carbonized oak leaf to a more standard format for use in laptops. According to the lead researcher of the Stanford study, Zhenan Bao, although Lithium offers a superior performance, its rarity and high cost is leading people to search for materials such as Sodium to build low-cost but high performance batteries.

The research team uses a battery with Sodium salt cathode and a Phosphorous anode—materials that are abundant in nature. Near the cathode, Sodium ions combine with oppositely charged myo-inositol ions. To improve the charge-recharge cycle, the researchers had to study the forces at work at atomic-level, when Sodium ions detach and attach from the cathode.

The newly developed Sodium-ion battery has a reversible capacity of 484 mAh/gm, which translates to an energy density of 726 Wh/Kg. The research team claims the energy efficiency of the new batteries to be greater than 87%. Regarding the cost comparison between similar storage capacity batteries, the team says the new Sodium-ion battery will cost less than 80% of the cost of a Lithium-ion battery of similar storage capacity.

To obtain more performance from the Sodium-ion battery, the research team is planning to work more on its phosphorous anode. In addition, to be able to dictate the size of the Sodium-ion battery necessary to store a certain amount of energy, the team also plans to examine the volumetric energy density in comparison to that of Lithium-ion batteries.

Faradion Limited, of Sheffield, UK, has developed Sodium-ion technology that offers energy densities in batteries far exceeding those of other known Sodium-ion technologies. In addition, their new technology produces energy densities that exceed those from popular Lithium-ion materials such as Lithium iron phosphate. Faradion makes current collectors in their Sodium-ion batteries from Aluminum rather than from the more expensive copper that Lithium cells use.

According to electrochemical tests Faradion has conducted, they list the advantages of the Sodium-ion materials over conventional Lithium-ion materials as follows—better rate capability, better thermal stability (safer), improved transport safety, improved cycle life, and similar shelf life. Further, Sodium-ion material processing is similar to that followed for Lithium-ion materials at every step, beginning from synthesis of the active materials to the processing of electrodes.

Innovate UK co-funds a project for Williams Advanced Engineering, where the novel Sodium-ion technology from Faradion is currently being employed to build 3 Ah prismatic cells. Williams is further incorporating these cells into batteries for commercial use.

Nano-Diamonds Help Prevent Lithium Battery Fires

Last year, airline flights banned Samsung Galaxy Note 7s because of its battery-related fires and explosions. Scientists researching the source of the runway beat buildup found the culprit to be small dendrites forming between the anode and cathode of the battery. A materials specialist from the Drexel University at Philadelphia has proposed a low-cost easy solution to preclude dendrite formation.

According to Drexel professor Yury Gogotsi, this simply requires mixing nanodiamonds with the regular lithium-ion electrolyte at one percent concentration. Gogotsi discovered the method along with a doctoral candidate from Tsinghua University at Beijing. However, Gogotsi found it rather easier to confirm that the nanodiamond additive works, than getting Samsung and several other OEMs and Li-ion battery producers to follow the concept.

Gogotsi had to use internal financial support from Drexel for proving the concept. They are now trying to interest industrial partners for funding to characterize the process in more detail. Specifically, they have yet to determine the amount of nanodiamonds necessary to add to the electrolyte for particular applications.

As Li-ion battery technology is already expensive, it is possible that cost-conscious manufacturers are wary of increasing the cost of batteries because of the addition of diamonds of the nanodiamonds. However, according to Gogotsi, the concern is rather unfounded, as, contrary to popular belief, nanodiamonds are not expensive, but cheap to manufacture. Moreover, they can be easily created from waste materials.

Gogotsi suggests a very simple method of manufacturing nanodiamonds. According to him, this is possible using expired explosives—otherwise expensive to dispose of—and exploding them in a sealed chamber. The coating on the walls of the chamber will have more than 50% nanodiamonds with a typical size of 5 nanometers. This is similar to Superman making diamonds from coal in the popular comic books. The presence of nanodiamonds in the electrolyte of a Lithium-ion battery prevents the formation of dendrites that create shorts resulting in runaway heat build-up and subsequent fires.

Although Gogotsi uses nanodiamonds in his lab, the process for creating them came from Russia. Three separate laboratories in Russia independently perfected the technique, which was kept very secret.

A description of the process finally emerged from a publication from the Los Alamos National Lab, and worldwide people use the technique to turn waste into marketable products. These hard-to-dispose-of waste products include the expired C4. Several manufacturers use nanodiamonds widely in their products. These include medical coatings, industrial abrasives, and magnetic field measuring electronic sensors.

According to Gogotsi and his team, the nanodiamonds work as an additive to the electrolyte to co-deposit with lithium ions, and produces dendrite-free deposits of lithium. This is because lithium prefers to adsorb onto the nanodiamond surfaces leading to a uniform deposit of lithium arrays. This uniform deposition of lithium enhances the cycling performance of the electrolyte, leading to a stable cycling of lithium.

As the nanodiamond co-deposition significantly alters the plating behavior of lithium, the process offers a promising method of suppressing the growth of lithium dendrites in batteries using the lithium metal.

Rechargeable Battery Packs Benefit From Integrated Battery Pack Monitor

Increasingly, electronic devices are depending on more than one battery unit for deriving power—driving motors require a higher voltage than does the control system. This includes energy storage systems, toys, scooters, e-bikes, handheld power tools, lawn equipment, and vacuum cleaners. So far, battery monitors could only monitor the entire battery pack and not the individual batteries making up the pack. Now, Intersil has developed a battery pack monitor with a difference. Not only can it monitor 3-to-8 cells simultaneously and individually within a pack, it can cater to different battery chemistries as well.

The battery pack monitor from Intersil, the highly integrated ISL94202, enables designers to restrict their design to only two terminals, while accurately monitoring, protecting, and balancing each cell of a rechargeable battery pack, thus ensuring their safe operation and charging.

Acting as a stand-alone protection system for batteries, the ISL94202 has an internal state machine sporting five pre-programmed modes. Apart from accurately balancing and controlling each cell in the battery pack, these modes also protect the entire pack from catastrophic events such as cell voltage over-discharge/ overcharge, short circuit conditions, and hardware faults. Additionally, the ISL94202 conforms to the pack safety requirements of IEC62133, UL2271/72, and UL2054 standards.

Using the ISL94202 does not require an external microcontroller. Designers can directly program the battery pack monitor, which Intersil claims can control the smallest and least expensive battery packs available in the industry. However, the ISL94202 has an I2C serial communication bus, through which it can transfer data such as the state of health, state of charge, and fuel gauge measurements related to the cells to an external microcontroller. The device has a high-side current measurement feature that enables precise fuel gauge status monitoring.

It is easy to interface the ISL94202 to tools or electric motor equipment, as the battery pack monitor integrates high-side FET drive circuitry for charging and discharging—keeping all electronics at ground level reference. The device also has external passive cell-balancing switch controls, which ensure proper cell energy matching, while protecting the cells individually from chronic undercharging. Manufacturing is greatly simplified as the ISL94202 has the capability to withstand hot plug events such as those happening during factory assembly of battery packs.

According to Philip Chesley, a senior vice president with Precision Products at Intersil, customers can expect all the necessary front-end battery features from the ISL94202, against catastrophic pack failures. The innovative high-side FET control can monitor current and cell measurement while delivering a small footprint solution for efficient battery pack designs.

ISL94202 has a temperature sensor interface, power FET control, current sense monitor, and automatic cell balance using a 14-bit ADC, all without needing recourse to an external microcontroller. It can handle cell voltage level shifts of up to 4.8 V per cell, while monitoring for different battery chemistries such as Li-ion FePO4, Li-ion Mn2O4, and Li-ion CoO2.

For cell balancing, the ISL94202 can use external FETs being driven by the internal state machine of the device, or an external microcontroller. Additionally, the ISL94202 covers the operational industrial temperature range of -40°C to +85°C, measures 6X6 mm, and comes in a 48-lead QFN package.

Non-Toxic Batteries for Humans and Fish

Lithium-ion batteries are very popular nowadays, as everyone has one in their cell phones. Although people use batteries of a large variety of technologies and form factors, everyone wants one with high energy density, low weight and volume, superior charge/discharge characteristics, and low cost. The Lithium-ion chemistry is popular, as it tends to meet most of the above desirable characteristics, even though it has several variations.

However, some applications need batteries with unusual construction, form factor, and chemistry, those that the Lithium-ion battery will simply be unable to meet. Consider, for instance, the research under the guidance of Professor Christopher Bettinger, at the Carnegie Mellon University.

The CMU researchers are interested in developing edible, biocompatible batteries. They want to use non-toxic material already present within the body for parts of the battery, such as the acid in the stomach, which they want to use as the electrolyte. For this, the team has developed anodes made of manganese dioxide, already present in the body, and cathodes based on melanin, which the body contains as a pigment. They also claim to have developed other versions of batteries consisting of body-friendly materials.

The researchers are interested in developing body-friendly batteries where the electrodes can dissolve harmlessly within the body after use. Among the batteries the group has developed using different types of soluble cations, most have terminal voltages ranging from 0.5 to 0.7 volts. Although information is still sketchy, one battery was able to deliver about 5 mill watts of power for nearly 20 hours.

However, it is not only humans who need such special batteries. Fish too need batteries to power tracking devices, so scientists can follow their trail and understand how they migrate. For instance, researchers at the Pacific Northwest National Laboratory have developed a battery small enough for injection, but powerful enough to enable tracking movements of salmon. This battery weighs only 70 mg, and has dimensions of 6×3 mm. It is handcrafted with several layers of rolled up material, thereby increasing the internal surface area, and reducing its internal resistance. The scientists have so far handmade over 1000 such rice-grain sized batteries, and implanted nearly 700 of them into fishes for powering tracking devices.

The tiny batteries supply enough power to send a 744-microsecond signal every three seconds for nearly three weeks, or every five seconds lasting over a month. That makes the average energy density of the batteries to be 240 WHr/kg. Compare this with standard silver oxide button microbatteries, which have an energy density of nearly 100 WHr/kg. So far, the scientists have not revealed how they made these measurements and whether the comparison is fair.

Making such small batteries comes with some peculiarly unique issues. One such issue is attaching leads for connection. The microbatteries from the Pacific Northwest have leads internally built in. However, it is not very clear how the researchers from the Carnegie Mellon University connect leads to their edible batteries, especially as the users of such special batteries do not have access to vendors for obtaining standard holders or connectors.

How Does An All Solid State Battery Work?

At the University of Texas at Austin, a 94-year old professor of engineering and his team continues to work on their invention—batteries. John Goodenough, one of the inventors of the most commonly used batteries — the lithium-ion battery. At present, Goodenough is working on an all solid state battery, a low-cost cell that offers a long life cycle, fast discharging and charging rates, and high energy density.

According to Professor Goodenough, one of the reasons for battery-driven cars not being widely adopted is the drawbacks associated with the commercially available lithium-ion batteries. Among the factors he includes are safety, cost, energy density, life cycle, and the rates of charging and discharging of the battery. Goodenough is of the view the all solid state battery will address all these problems.

As the journal, Energy & Environmental Science describes it, the non-combustible battery has an energy density of nearly three times that of lithium-ion batteries currently in use. As an electric vehicle derives its driving range from the energy density of the battery cell, a higher energy density helps to propel the vehicle more kilometers between charges. The number of discharging and charging cycles that the UT Austin battery allows is also greater, and that equates to batteries that are longer lasting. Where the typical charging time for batteries in use today is in hours, the researchers claim their battery attains full charge within minutes.

The difference between the two types of batteries lies in their electrolyte. At present, batteries we commonly use contain a liquid electrolyte for transporting ions between their anode and cathode. When charged very quickly, metal whiskers or dendrites form on the electrodes, and these can traverse through the liquid electrolyte to form a short circuit. The result can result in explosions and fires.

The new battery replaces the liquid electrolyte with a glass-based one, and normal electrodes with alkali-metal anodes. According to Goodenough and his senior research fellow, Maria Helena Braga, this prevents the creation of dendrites, mitigating the hazard of short circuits.

Additionally, in the glass electrolyte, there is no lithium. Rather, the researchers have used low-cost sodium instead. Sodium is cheaper, as it can be easily extracted from widely available seawater. According to Braga, that makes the new batteries much more environment friendly compared to those containing lithium-ions.

Conventional batteries cannot use alkali-metal anodes with lithium, sodium, or potassium. However, this technology allows the new batteries to attain their high energy densities and longer life cycles.

Plummeting temperatures freeze up the liquid electrolyte, preventing normal batteries from operating in low temperatures. This has been a major obstacle in practical use of batteries. However, the all-soli-state glass electrolyte has no such drawbacks, and can easily operate down to extremely cold temperatures of -20°C.

Braga began working on solid-state electrolytes while still in the University of Porto in Portugal. She has been collaborating with Professor Goodenough and Andrew J Murchinson, another researcher at UT Austin, since two years ago.
The glass electrolyte simplifies fabrication of the battery cell, as it allows them to plate the alkali metals and strip them on both the anode and the cathode sides, without creating dendrites.

Super Efficient Diamond Batteries from Nuclear Waste

So far, we have been dumping our dangerous nuclear waste into oceans or deep inside the earth, hoping they will stay there. Now, there is a better way out. Scientists are now confident they can use nuclear waste as a source of energy to convert radioactive gas into diamonds of the artificial type, not as jewelry, but to be used as batteries.

Scientists claim the diamonds can generate their own electrical current. As they are made of radioactive material with long half-life, the batteries could potentially provide power for thousands of years. According to Tom Scott, a geochemist from the University of Bristol in the UK, the batteries will simply produce direct current, without emissions, and without requiring any moving parts or maintenance.

The radioactive material, encapsulated within a diamond, will turn the long-term problem of handling nuclear waste into a nuclear powered battery producing a long-term supply of clean energy. As a demonstration of their claims, Scott’s team has developed a prototype diamond battery using an unstable isotope of Nickel-63 as its source of radiation.

The half-life of Nickel-63 is approximately 100 years. That means after 100 years, the prototype battery would still be retaining about 50 percent of its original charge. However, the scientists claim they have an even better source for making these batteries. They want to use the huge quantities of nuclear waste generated and stockpiled by UK.

From the 1950s through the 1970s, the first generation of Magnox nuclear reactors in the UK used graphics blocks to sustain nuclear reactions. However, the graphite blocks turned radioactive and generated an unstable carbon isotope, the Carbon-14.

Although UK had retired the last of these Magnox reactors by 2015, the decades of power generation has left a huge amount of nuclear byproduct as waste—nearly 95,000 tons of radioactive graphics blocks need to be safely stored and monitored.

Additionally, as Carbon-14 has a half-life of 5,730 years, UK may have to take care of this dangerous waste for a long, long time. However, it also means this material could be used to make batteries that last an amazingly long time—provided scientists could repurpose them into the diamond structure, just as they did with Nickel-63.

Carbon-14 emits only short-range radiation, one quickly absorbed by any nearby solid material. According to Neil Fox, one of the researchers, although touching or ingesting Carbon-14 would be dangerous, encasing it within diamond would prevent any short-range radiation from escaping. Moreover, diamond would offer the ultimate protection, as it is the hardest substance known to man.

The team presented their ideas at a lecture at the University of Bristol, but has yet to publish their research. The researchers claim that although Carbon-14 batteries would be good for low-power applications, their endurance would be on an entirely different scale.

For instance, an alkaline battery weighing 20 grams has an energy density of 700 Joules/gram, giving a life of 24 hours of continuous usage.

On the other hand, a diamond battery with 1 gram of C-14 will deliver only 15 Joules per day. However, it will continue to produce this level of output for more than 5,730 years—giving a total energy density of 2.7 TeraJoules/gram.