From lab to grid: how living batteries could transform the energy landscape

Many raw materials for conventional batteries are already scarce and often mined by child laborers. Another area for improvement is that a relatively small number of countries in the world have most of these in-demand resources. Such a concentration has caused supply chain challenges. Many scientists, engineers, and other concerned parties recognize the need for improvements in sourcing battery materials and creating more sustainable power sources.

Some are focusing on so-called living batteries or bio-batteries. Although the specifics vary per project, these creations usually feature materials and components sourced from nature. What have some of the scientists working on these creations done so far?

Making batteries last longer

Despite batteries’ convenience, changing them can be a major ordeal. Switching out the batteries of an alarm clock is a simple act. Still, it’s a much different story when the device is a patient’s pacemaker or an industrial sensor used to monitor essential equipment in a remote or dangerous area. These real-life use cases encourage scientists to progressively look for or create batteries that last much longer than many currently available options.

Working toward century-long battery life with bacteria

A team has examined whether spore-forming bacteria could power a tiny microbial fuel cell. Researchers hoped to create something to tolerate long storage periods without showing a degradation of biocatalytic activity. They also wanted this bio-battery to be a portable, easy-to-store option people could activate with moisture from the air.

The group sealed the bio-battery with a material that can withstand temperatures of minus 500 to 750 degrees Fahrenheit, increasing the likelihood of people using it in a wide variety of settings.

The researchers also tested their creation by unsealing the covered parts of the battery to expose them to moisture. Then, the battery’s bacteria was mixed with a chemical germinant, causing the microbes to produce spores. The resulting reaction was potent enough to power an LED light, a small clock, or a digital thermometer. That’s notable, given the fuel cell was only the size of a dime.

Experiments also showed the team could cut the time required to fully charge the battery by activating the bacterial spores with heat. The warmth reduced the charging time from 60 minutes to 20. Plus, when the charging happened in a high-humidity environment, the battery showed comparatively higher electrical output than during exposure to lower-humidity conditions. Understanding more about those variables will help this research team and others involved in similar work learn how to optimize bio-batteries in the future.

The researchers also checked how storing the bio-battery at room temperature for a week might affect its performance. That test caused just a 2% drop in power generation, suggesting people need not worry about using the battery constantly to ensure it performs as expected. The researchers hope this battery will work for up to 100 years but must do more tests to study the longevity aspect.

Pursuing electric vehicle battery improvements

Although most people view electric vehicles as more sustainable than gas-powered ones, the situation is more complex when it comes to manufacturing and sourcing. For example, although a driver can make a significant carbon footprint change by switching to an electric vehicle, there are still associated emissions when manufacturing that greener vehicle.

Similarly, issues exist with sourcing battery materials for these eco-friendly cars. Lithium mining is a water-intensive activity that can disrupt local ecosystems through various processes. Researchers have also found a leak from one lithium mine, an event suspected to have killed local wildlife, including cows, yaks, and fish. These downsides emphasize why people must aggressively develop and search for more environmentally friendly solutions.

Developing anodes from lignin

In one example, a Finnish company prioritizes electric car battery technologies powered by a compound found in trees. One of the main goals of this approach was to replace the graphitic carbon in lithium-ion batteries with lignin, an organic polymer. More specifically, the company uses lignin within its battery anodes. However, getting it to the correct form is an in-depth process.

A representative explained how lignin extraction occurs during cellulose fiber production. It then gets refined into a fine, hard carbon powder that becomes an active material in a lithium-ion battery’s negative anode.

People use the powder to manufacture sheets and rolls of electrodes. Finally, manufacturers incorporate those electrodes alongside other components to create the batteries.

Lignin has compelling potential benefits over graphitic carbon. For example, it charges more quickly and performs better in cold temperatures. The people working on this project point out how lignin is a renewable resource already abundantly produced in parts of the world, including Europe.

Although it’s too early to say how easily researchers could scale the work, they have many appealing reasons to try. The company behind this project is well-positioned to contribute to the supply chain if these lignin batteries become more widely available. One of its mills is the world’s largest lignin producer, boasting an annual capacity of 50,000 tonnes.

Working with a biodegradable electrolyte to curb e-waste

As many government leaders and others in positions of power urge people to switch to electric vehicles, some concerned parties have wondered how much the transition will contribute to more e-waste. Some facilities specifically focus on recycling electric vehicle batteries, and their work is undoubtedly useful. However, this problem requires assessing multiple solutions, including designing more sustainable batteries. Problem-solving mindsets and approaches will help.

Consider how researchers developed a zinc-based battery featuring a biodegradable electrolyte. They turned their attention to crab shells. One person working on the project clarified that the polypropylene and polycarbonate separators take hundreds or thousands of years to break down, but most lithium-ion batteries currently use them.

Conventional batteries typically have flammable or corrosive electrolytes, too. This team created a gel electrolyte from chitosan, a biological material most commonly found in crustacean exoskeletons. The biodegradable nature of this electrolyte means microbes can break down about two-thirds of it. The zinc is the only component left, and researchers used that metal component instead of lithium or lead.

Tests showed the battery remained 99.7% energy-efficient after 1,000 cycles. Although the unsustainability of current electric car batteries was one factor in this work, researchers believe the progress could result in better methods of storing renewable energy and transferring it to the grid.

This team will continue their work on making these biodegradable batteries even more sustainable. They hope to eventually design options that will fully break down rather than contribute to already overflowing landfills. The group will also explore biodegradable ways to facilitate the manufacture of bio-based materials.

Creating a bio-battery to store renewable energy

Renewable energy has rapidly become significantly more accessible. Consider how, in 2022, solar power was 29% less expensive than the most economically priced fossil fuel. However, in 2010, solar power cost 710% more than that same fuel.

Renewable energy’s variable output is one of its downsides. Solar farms typically produce more power during bright days than heavily cloudy ones. Similar variations exist for wind turbines on breezy days versus relatively calm ones.

People have developed batteries to store excess renewable energy for later use. That way, households and businesses can still rely on green energy during unfavorable weather conditions.

Building a bio-battery that stores and releases heat

A team at a Norwegian lab explored how to store energy from the building’s solar panels while going outside the limitations of current battery-based technologies. The group built a bio-battery with phase-change materials (PCMs) that have phase-dependent behaviors and can store heat. The prototype looks like a small, silver container with several pipes going into and out of it.

This device’s composition is 90% PCM, and it can store and release heat. Those actions occur via a heat exchanger and 24 plates that send the warmth into water that works as an energy carrier. The bio-battery also contains three tonnes of vegetable oil-based, non-consumable liquid bio-wax that begins to melt at the average human body temperature.

The researchers tested their bio-battery in their laboratory’s heating system for more than a year. Once cold water circulates through the battery’s heat-storage components, the device heats the liquid and sends it to the building’s radiators and ventilation. This approach enables heating the lab with as much on-site-generated solar energy as possible.

Further experiments revealed scientists should charge the battery before peak-demand periods. Ensuring it’s ready to go during the coldest parts of the day prevents the building from becoming overly dependent on the grid at the most expensive times. The researchers believe they can further tweak their process to take advantage of spot-price fluctuations which determine how much the lab pays for grid energy.

A brighter, battery-based future

Bringing the above creations from the lab to the real world isn’t easy. The achievements in controlled environments show scientists they’re on the right track. However, scalability and performance issues sometimes arise when people attempt to use innovations outside the lab, despite previous successes.

It could also take time to convince some people these creations are worth their attention. Even when individuals notice the need for change, some naturally resist or question it. Suppose consumers can get less sustainable, conventional options easily at reasonable prices. Then, some will balk at starting to use bio-batteries that are harder to find and will likely be more expensive than their counterparts at first.

People must acknowledge and do their best to account for these obstacles, understanding lasting change doesn’t often come easily.

However, the progress made so far, as well as the progress that continues to shape this important work is undeniably promising.

Even when scientists encounter inevitable issues, they’ll learn things to further their efforts and help others in the field. These creative examples of living batteries will help others get excited about trying to go beyond previous possibilities.