Batteries Mimic Multilayer Geometry of Mammal Bones for Structural Stability
By copying the multilayer geometry of mammal bones, cathodes for sodium-ion batteries can be made more structurally stable, while maintaining high capacities and fast charge rates.
Sodium-ion batteries are poised to replace lithium-ion batteries for large-scale electrical energy storage. They offer several advantages over lithium-ion batteries, particularly due to the widespread abundance of sodium.
However, it is difficult to develop sodium cathodes, materials through which electrons can enter a battery. Many candidate materials are unstable or cannot withstand high voltages.
To find a solution, researchers from Sungkyunkwan University, the University of Texas at Austin, and Brookhaven National Laboratory turned to nature. They describe their mammal bone-inspired sodium cathode in the journal Applied Physics Reviews, from AIP Publishing.
“We believe that nature provides a very promising solution to resolve technical problems,” said Ho Seok Park, one of the authors. “Accordingly, we tried to find the ideal architecture that can resolve these kinetic and stability limitations.”
Mammal bone structures consist of an inner porous, spongy bone that allows the storage and transport of bone marrow, surrounded by a hard, compact bone, which offers mechanical and structural integrity under severe stress.
Following this design architecture, the group created a porous system of Na3V2(PO4)3 structures, also known as NVP, surrounded by a dense shell of reduced graphene oxide (rGO). NVP is a sodium cathode material that transports sodium ions rapidly but is structurally unstable.