Effect of K-doping on the Electrochemical Performance of Ca3Co4O9 Anode for Li-ion Batteries

Ca3Co4O9 (CCO) and Ca2.95K0.05Co4O9 (CKCO) powders have been prepared by the polyacrylamide gel method. CKCO shows increased capacity and better cycling stability compared with CCO. After cycled for 50 cycles at 0.5 C, CKCO retains a capacity of 223 mAh.g(-1), almost twice than CCO. The electrochemical impedance spectroscopy (EIS) tests shows the CKCO sample has a lower initial charge transfer resistance (R-ct) and undergoes smaller R-ct change during cycling than the CCO sample, indicating improved electrochemical performance by K-doping.