Promoting the electrochemical performance of commercial LiMn2O4 by hydrothermal modification with poly (vinylidene fluoride)

Abstract

The fast capacity decay and poor rate performance hinder the application of commercial LiMn2O4 (LMO) cathode in Li-ion batteries despite the low cost and environmental friendliness. Herein, commercial LMO was hydrothermally modified with poly (vinylidene fluoride) (PVDF). The PVDF-modified LMO with 1.0 wt% PVDF exhibits excellent rate performance (delivering discharge capacities of 128.2, 121.7, 112.4, 99.9, 85.5, 62.4 mAh g−1 at current densities of 20, 50, 100, 200, 400, 800 mA g−1, respectively) and superior cyclability (attaining capacity retention above 90% after 150 cycles at 100 mA g−1). The enhanced performance associates with the uniform PVDF coating on the surface of LMO particles (which suppresses the dissolution of Mn-ions in electrolyte to maintain the structural stability of LMO) and F-doing in LMO (which improves Li+ conductivity and reversible capacity). The PVDF-modification may push the application of the commercial LMO cathode forward.