Yokohama National University scientists have teamed up with researchers from the University of New South Wales (UNSW) in Australia to develop a positive electrode material for solid-state batteries that retains its volume after repeated charging cycles.
The material, Li8/7Ti2/7V4/7O2, is a binary system of optimized portions of lithium titanate (Li2TiO3) and lithium vanadium dioxide (LiVO2). When ball-milled down to an appropriate particle size in the order of nanometers, it offers high capacity due to its large quantity of lithium ions that can be reversibly inserted and extracted during the charge/discharge process.
The researchers tested the new positive electrode material in an all-solid-state cell by combining it with an appropriate solid electrolyte and a negative electrode. The cell exhibited a remarkable capacity of 300 mA.h/g, with no degradation over 400 charge/discharge cycles, as reported in Nature Materials. “The absence of capacity fading over 400 cycles clearly indicates the superior performance of this material compared with those reported for conventional all-solid-state cells with layered materials,” said Associate Professor Neeraj Sharma from UNSW Sydney. “This finding could drastically reduce battery costs. The development of practical high-performance solid-state batteries can also lead to the development of advanced electric vehicles.”
Why are solid state better that conventional?
Conventional batteries have one significant drawback, however. That semi-liquid paste is often flammable. If a short circuit occurs within the cell, it can overheat and burst into flames, often in rather spectacular fashion.
Solid-state batteries avoid that risk. They may also have somewhat longer life and higher energy densities than conventional cells. Lastly, because the risk of fire is so low, they can be charged more quickly using higher power charging equipment. Whether or not all this goodness will come with a higher price tag than conventional batteries is unknown at this time.
- https://cleantechnica.com/2022/12/22/solid-power-quantumscape-begin-shipping-solid-state-batteries-for-trials/
- https://www.pv-magazine.com/2022/12/13/the-mobility-revolution-high-capacity-electrode-material-for-ultra-stable-solid-state-batteries/