Microwave synthesis of copper network onto lithium iron phosphate cathode materials for improved electrochemical performance

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Herein reported is an efficient microwave-assisted (MA) approach for growing Cu network onto LiFePO4 (LFP) powders as cathode materials for high-performance Li-ion batteries. The MA approach is capable of depositing highly-porous Cu network, fully covered the LFP powders. The electrochemical performance of Cu-coated LFP cathodes are well characterized by charge/discharge cycling and electrochemical impedance spectroscopy (EIS). The Cu network acts as the key role in improving the specific capacity, rate capability, electrode polarization, as compared to fresh LFP cathode without the Cu coating. The EIS incorporated with equivalent circuit reveals that the completed Cu network obviously suppresses the charge transfer resistance. This result can be attributed to the fact that the Cu network ensures the LFP crystals to get electron easily, alleviating the electrode polarization in view of one-dimensional Li+ ion mobility in the olivine crystals. Based on the analysis of Randles plots, the relatively higher Li+ diffusion coefficient reflects the more efficient Li+ pathway in the LFP powders through the aid of porous Cu network.