Nickel Hexacyanoferrate-Modified LiFePO4 Cathodes with High-Rate and High-Pulse Current Charge-Discharge Capabilities

• Main Authors: Kuan-Yu Chao, 趙冠宇
• Other Authors: 邱國峰
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/57004706193694668747

碩士 === 逢甲大學 === 綠色能源科技碩士學位學程 === 104 === Nickel hexacyanoferrate (NiHCF) was synthesized by reverse micelle method and was coated on LiFePO4 (LFP) cathodes to improve the high-rate and pulse-current charge-discharge performances. This NiHCF has a low-strain open framework structure and exhibits a redox potential similar to that of LFP. The NiHCF-modified LFP cathodes show improved high-rate capability, with a 10 C discharge capacity that is 15% higher than that of pristine LFP. The NiHCF-modified LFP can endure high-pulse current charge-discharge, which is well suited for green energy grids. The modified and pristine LFP cathodes were operated with alternate pulse currents of 0.01 C and 5 C introduced into a 0.2 C discharge/charge process to simulate the conditions of green grids. The modified LFP cathodes exhibited a capacity retention of 92% after 50 cycles, whereas the pristine sample showed a capacity retention of only 75%. These results can be attributed to the reduction of electrode/electrolyte interface resistances due to NiHCF coating, as demonstrated by electrochemical impedance spectroscopy.