Renewables in general and electric vehicles in particular both have Achilles heels —storage. Even devices such as mobile phones suffer from battery life issues due to the growing need for computing. Heavy investments in new generation batteries provide grounds for optimism, but solar and wind farms need to make breakthroughs to provide a stable supply. One area of his research is the transition from lithium batteries to sodium batteries, the latter being a much more affordable material. However, the development of sodium cathodes has proven to be a challenge for researchers. Fortunately, the answer seems to lie in a new lesson. biomimicry, that is, the application of processes and structures from nature. In this case, the solution lies in mammalian bones.
This innovative technology project is the result of collaborative research between the University of Texas (USA), Sungkyunkwan University (Korea) and Brookhaven National Laboratory. To develop a more robust and stable sodium cathode, they closely examined mammalian bone structure. Mammalian bones consist of a hard exterior and a spongy interior that stores and transports bone marrow. This morphology provides tremendous mechanical strength to withstand large pressures. Under these premises, an international team created a porous structure known as NVP, coated with a layer of reduced graphene oxide (rGO). NVP offers excellent conductivity to sodium ions, but is a very fragile structure.
By combining the cathode with a graphene coating as if it were a bone, we have succeeded in significantly improving the structural integrity that mitigates degradation due to mechanical and electrochemical stress. One of the key advantages of these new sodium batteries is their ultra-fast charging speed and high resistance as they retain 90% capacity after 10,000 charging cycles. However, we still need to do a lot of testing before reaching a commercial version.
from bone to muscle
Another example of a biomimetic battery is a project at MIT in the United States. Instead of using bone structure, we are inspired by the properties of muscle. In collaboration with Southwest University, researchers investigated how muscle fibers transport blood, oxygen and nutrients and developed a new electrode type. Instead of muscle cells, the team used tiny spheres of carbon containing tellurium. Additionally, they used carbon nanotubes to act as a conductive material comparable to blood flow. The carbon spheres then act as storage cells.
Studies have shown that the prototype can withstand 500 charging cycles, which is still far from commercial use. But research published a few years ago already pointed to the potential of bio-inspired systems for energy storage.
If you want to learn more about the new generation of alternative batteries currently being developed around the world, I recommend this article on eggshell-based batteries, or this article exploring the use of wood waste. Another example is the technology that enables paper-based batteries.
sauce: Phys.org, Elsevier
