The Surface Coating of Commercial LiFePO by Utilizing ZIF-8 for High Electrochemical Performance Lithium Ion Battery.

The requirement of energy-storage equipment needs to develop the lithium ion battery (LIB) with high electrochemical performance. The surface modification of commercial LiFePO (LFP) by utilizing zeolitic imidazolate frameworks-8 (ZIF-8) offers new possibilities for commercial LFP with high electrochemical performances. In this work, the carbonized ZIF-8 (C) was coated on the surface of LFP particles by the in situ growth and carbonization of ZIF-8. Transmission electron microscopy indicates that there is an approximate 10 nm coating layer with metal zinc and graphite-like carbon on the surface of LFP/C sample. The N adsorption and desorption isotherm suggests that the coating layer has uniform and simple connecting mesopores. As cathode material, LFP/C cathode-active material delivers a discharge specific capacity of 159.3 mAh g at 0.1C and a discharge specific energy of 141.7 mWh g after 200 cycles at 5.0C (the retention rate is approximate 99%). These results are attributed to the synergy improvement of the conductivity, the lithium ion diffusion coefficient, and the degree of freedom for volume change of LFP/C cathode. This work will contribute to the improvement of the cathode materials of commercial LIB.