Batteries are an important technology for combating CO2 emissions from the transportation, power, and industrial sectors. To be effective in achieving that goal, batteries must demonstrate ultra-high performance that exceeds their current capabilities: energy and power performance nearing theoretical limits, exceptional longevity and dependability, and enhanced safety and environmental sustainability. Furthermore, in order to be economically viable, these batteries must be scalable, allowing for cost-effective large-scale production.
Lithium-ion batteries are now the most widely used energy storage solution for mobile electronic gadgets and electromobility. When it comes to batteries, though, there is always room for improvement: batteries that are less expensive, safer, last longer, are more energy dense, and are easily recyclable. With this idea in mind, bio-batteries come to our rescue.
Bio batteries are created from ingredients that are fully safe, organic, non-combustible, and biodegradable. These batteries may be recharged using our bodies’ extra energy rather than an outlet. Refueling through the collection of kinetic energy from our activity, thermal energy from body heat, or—in the most sci-fi scenario—feeding on the biochemical surplus of sugars rushing through our veins, or even substances contained in our saliva, sweat, or other body fluids. This concept is known as biobattery, and its prospective applications and benefits are quite astonishing. The idea is a simple take on the classic battery. When charging a lithium-ion battery, lithium ions and electrons accumulate at the anode, and the return movement of electrons over an external circuit, from anode to cathode, at the same time that lithium ions return to the cathode through an ion-selective separator, powers your device.
The usual biobattery or biofuel cell exists only in a condition similar to that of a charged battery. The electrons have already arrived at the anode, but they are trapped in organic molecules like glucose. These compounds are oxidized by isolated enzymes or enzymes found in entire microorganisms to liberate electrons and protons. From here, the procedure is nearly identical to that of a lithium-ion battery. Although this cathode reduction process sometimes includes enzymatic or microbial activity, the electrons and protons eventually recombine with an acceptor molecule. The strategy mimics and leverages the natural biochemical mechanisms that allow organisms to derive energy from food—electrons are extracted from organic fuel and transferred to electron acceptors like the terminal acceptor oxygen used in aerobic respiration. In animals, the energy from electron mobility is eventually trapped in ATP, which provides energy for the majority of metabolic operations. However, just as electrons drive ATP synthesis in cells, electrons in biobatteries generate current by passing electrons through an external circuit.
The concept of biobatteries is not new. Sony made a splash in 2007 when it demonstrated that a succession of basic enzyme-based biobatteries powered by glucose could power small devices such as a flash-based mp3 player. Sony never made public their declared plan to employ their designs in small toys. The key motivations for one form of the biobattery are to move away from fossil fuels and metals that are scarce, poisonous, or involved with geopolitical issues while reducing battery weight. CFD Research at Huntsville, Alabama, for example, is developing biobatteries with military applications in mind. These cells are powered by glucose or alcohol and use enzymes to extract electrons from the fuel source and generate energy. Combined with solar cells, the net effect can be a lightened load for soldiers needing to power radios, GPS, night-vision goggles, vehicles, etc. This pioneering work of biofuel cells did not have clear applications and was considered a replacement for conventional high-power supplies (such as lithium-ion batteries).
The development of a “papertronic” spit-powered biobattery in 2016. It was made up of freeze-dried electrogenic bacteria in a reservoir, a nickel and polypyrrole/carbon black anode, a wax-based ion exchange membrane, and an activated carbon-based air cathode (with oxygen as an electron acceptor), all printed on paper that could be easily folded to form the necessary interfaces. Aside from spit, nearly any other human fluid, puddle water, or wastewater can be utilized to reanimate the bacteria while also providing the necessary fuel to enable energy production—enough to power an LED for around 20 minutes, at least with a 16-battery stack. These paper batteries have a lot of potential for application in the internet of disposable things (IoT)—single-use devices that may be used to trace shipments, for point-of-care medical diagnostics, food and beverage tracking, and so on.
But, what are the new developments in this field of producing sustainable and efficient bi-batteries? Scientists are now trying to imitate animals that produce their own electricity: electric eels. Electric eels are the most well-known electrogenic creatures. Electrogenic animals are capable of producing their own electricity. There are creatures that can smell electricity as well. They are known as electroreceptive. The vast majority of electrogenic animals are also electroreceptive. However, many electroreceptive animals are not electrogenic. Echidnas, platypuses, bees, spiders, dolphins, sharks, and rays are examples of electroreceptive creatures. Some bacteria, yeast, and fish are electrogenic as well.
The electric eel produces huge electric currents using a highly sophisticated neural system that can synchronize the activity of disc-shaped, electricity-producing cells packed into a specialized electric organ. The neurological system does this via a command nucleus, which determines when the electric organ will fire. When the command is sent, a complex network of nerves ensures that thousands of cells, no matter how far they are from the command nucleus, activate at the same time. Each electrogenic cell has a negative charge of about 100 millivolts on the outside compared to the inside. When the command signal is received, the nerve terminal emits a brief burst of acetylcholine, a neurotransmitter. This produces a low-resistance transient channel between the inside and outside of one side of the cell. As a result, each cell acts like a battery, with the activated side carrying a negative charge and the opposing side carrying a positive charge.
Because the cells are arranged inside the electric organ like a stack of batteries, the current generated by an activated cell “shocks” any inactive neighbor into activity, triggering an avalanche of activation that lasts only two milliseconds. This nearly synchronous start-up generates a brief current that flows along the eel’s body. If the eel lived in air, the current could reach one ampere, transforming the creature’s body into a 500-volt battery. However, eels dwell in water, which gives extra current outlets. They produce a higher voltage but a divided, and hence reduced, current.
This amazing discovery to generate electricity using an animal’s body is not fully complete. Still, many scientists work to produce the maximum amount of energy and to create the best imitation of electric eels’ cells. When it is complete, this discovery will have many applications and benefits.
Adams, Cecil. “Can You Harness Electricity from Electric Eels?” Connect Savannah, 12 Aug. 2022, http://www.connectsavannah.com/savannah/can-you-harness-electricity-from-electric-eels/Content?oid=6418286.
Agarwal, Tarun. “What Is a Bio-Battery – Working Principle, Types, Applications and Potential.” ElProCus – Electronic Projects for Engineering Students, 5 Dec. 2018, http://www.elprocus.com/an-overview-of-bio-battery-working-principle-types-applications.
“Models of Eel Cells Suggest Electrifying Possibilities.” NIST, 27 Nov. 2017, http://www.nist.gov/news-events/news/2008/10/models-eel-cells-suggest-electrifying-possibilities.
Proffitt, Kyle. “Releasing the Potential of Biobatteries.” Bio IT World, 2022, http://www.bio-itworld.com/news/2022/02/09/releasing-the-potential-of-biobatteries.
Science, Let’S Talk. “Generating Electricity: Electric Animals.” Let’s Talk Science, 27 Nov. 2020, letstalkscience.ca/educational-resources/backgrounders/generating-electricity-electric-animals.