It had been firmly believed that it would be challenging to insert K ions into graphite electrochemically although extraction of K ions from KC8 was reported. This technology for the first time discovered that graphite, soft carbon and hard carbon can reversibly insert K ions with a capacity up to 260 mAh/g in a non-aqueous electrolyte. This capacity is very close to 279 mAh/g when assuming KC8 forms. The fact that graphite functions as a KIB anode does provide an advantage for KIBs over NIBs considering the scale of graphite anode industry established for LIBs.
Features & Benefits
Background of Invention
Li-ion Batteries (LIBs), the state-of-the-art batteries, fall short of meeting requirements for stationary batteries that are indispensible to enable the deployment of renewable energy sources, including solar and wind power. This is due to the scarcity and high cost of lithium. The basic requirements for stationary batteries are low cost and minimum maintenance. This calls for alternative battery technologies based on Earth abundant elements. Na-ion batteries (NIBs) and K-ion batteries (KIBs) are very attractive because sodium and potassium occupy 2.3 %wt. and 1.5 %wt. of Earth crust, respectively, in contrast to 0.0017 %wt. for lithium. For NIBs, fast progress is being made on the cathode side, where Na-ion based layered metal oxides and polyanionic compounds demonstrate encouraging capacity and cycling life. However, the real hurdle that prevents NIBs from commercialization is the lack of high performance anodes.