Effects of Boric Acid Tris-(2-oxo-[1,3]dioxolan-4-ylmethyl) Ester as an Additive on the Electrochemical Performance of Graphite Anode

Abstract

To improve the cycle performance of lithium ion battery (LIB), boric acid tris-(2-oxo-[1,3]dioxolan- 4-ylmethyl) ester (BATE) as a novel electrolyte additive in 1mol•L-1 LiPF6-EC:DMC (1:1 vol., Lithium Battery-grade) electrolyte was investigated. BATE derived from glycerol carbonate, which had the same ring structure as ethylene carbonate (EC). Additionally, the carbonyl group (-C=O) and electron deficient boron atom contained in the BATE molecular structure had been proved to be effective in maintaining the stability of the lithium salt (LiPF6) and increasing the durability of the electrolyte for formation of a solid electrolyte interface (SEI) layer, which plays a critical role in the cycle life of lithium ion battery (LIB). The electrochemical measurements and investigations of the compound BATE as additive were carried out by charge-discharge test, electrochemical impedance spectroscope (EIS), cyclic voltammetry (CV) test and scanning electron microscope (SEM). Results confirmed that BATE decomposed on the graphite anode earlier than electrolyte solvents to form the solid electrolyte interface (SEI) film. BATE could improve cycle stability of the cell significantly, especially when addition of 1.0% BATE, the capacity retention was up to 98.1% after 20 cycles. And the internal resistance change of cell with cycles was decreased after 20 cycles.