Title

Improving the performance of graphite/LiNi0.5Mn1.5O4 cells with added N,N-dimethylformamide sulfur trioxide complex

Document Type

Article

Date of Original Version

1-1-2017

Abstract

N,N-dimethylformamide sulfur trioxide complex (DMF-SO3) has been investigated as an electrolyte additive for LiNi0.5Mn1.5O4/graphite cells cycled to 4.8 V. Addition of 0.1% DMF-SO3 to 1.2 M LiPF6 in EC/EMC (3/7, v/v) standard electrolyte (STD) results in a significant improvement in the capacity retention and coulombic efficiency of LiNi0.5Mn1.5O4/graphite cells after 50 cycles at 45◦C. Ex-situ surface analysis of the electrodes after cycling has been conducted via scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy with attenuated total reflectance (IR-ATR). The surface analysis suggests that a uniform interfacial film is formed on the LiNi0.5Mn1.5O4 surface composed of the decomposition products of DMF-SO3. The novel cathode surface films passivates the surface at high potential leading to the improved electrochemical performance.

Publication Title

Journal of the Electrochemical Society

Volume

164

Issue

13

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