Controllable Morphology Tailoring with Solvothermal Method Toward LiMnPO4/C Cathode Materials for Improved Performance and Favorable Thermostability

An environmentally friendly method for the synthesis of LiMnPO4/C anode material for lithium-ion batteries by solvothermal method is introduced. The modification of the morphology of this precursor is altered by changing the ratio of the conditioning solvent (water-ethylene glycol solution) and the order of material addition. Ethylene glycol (EG) exerts a considerable influence on synthesizing LiMnPO4/C flake-like nanocrystal, which benefits the extraction/insertion reaction of lithium ions and improves the electrochemical activity and electrochemical performance of LiMnPO4/C material. When the solvent composition is H2O:EG = 1:3, exhibiting exceptional charge/discharge performance and rate capability, the specific discharge capacities are 155.8, 153.7, 148.8, 141.4, 129.5, and 112.6 mAh g−1 at the 0.1, 0.2, 0.5, 1, 2, and 5 C rates, respectively. When the charge–discharge rate returns to 0.1 C, the LiMnPO4/C material shows a reversible discharge specific capacity of 153.7 mAh g−1. Differential scanning calorimetry (DSC) tests verify that the thermodynamic stability of the prepared LiMnPO4/C(LMP) and commercial LiFePO4 (LFP)materials is better than that of commercial nickel–cobalt-aluminum (NCA) ternary materials. These prepared LiMnPO4/C composites have high electrochemical capacity and cycle stability.