Improved Reversibility of PF6 (-) De/intercalate in Graphite by Building the Artificial PVDF-HFP Polymer Cathode Electrolyte Interphase

As a typical cathode for Li-dualion batteries (Li-DIBs), thoughgraphite can store anions, the high working voltage up to 4.5 V vsLi(+)/Li brings about low Coulombic efficiency (CE), unsatisfactorycyclability, and fast battery failure. Here, we demonstrate that thegraphite with an artificial PVDF-HFP polymer cathode electrolyte interphase(CEI) layer can effectively suppress electrolyte decomposition, improvethe CE, and stabilize the graphite structure in the progress of PF6 (-) de/intercalation. Such a CEI-reinforcedgraphite cathode shows prolonged cyclability with a 76% capacity retentionratio after 1000 cycles at a cutoff potential of 5.2 V versus Li+/Li and more attractive rate performance. This work displaysa feasible method for developing Li-DIBs with satisfactory cycle stabilityand high power performance.

Automated summary

This study demonstrates that the use of an artificial PVDF-HFP polymer cathode electrolyte interphase (CEI) layer on the graphite anode surface can effectively suppress electrolyte decomposition, improve the Coulombic efficiency, and stabilize the graphite structure, resulting in improved cycle stability and power performance for Li-dualion batteries.