Document Type

Article

Date of Original Version

2015

Department

Chemistry

Abstract

Lithium tetramethyl borate (LTMB, LiB(OCH3)4) has been prepared and investigated as a novel cathode film forming additive to improve the performance of LiNi0.5Mn1.5O4 cathodes cycled to high potential (4.25-4.8 V). Addition of LTMB to 1.2 M LiPF6 in EC/EMC (3/7, v/v) improves the capacity retention of graphite/LiNi0.5Mn1.5O4 cells cycled at 55°C. The added LTMB is sacrificially oxidized on the surface of the cathode during the first charging cycle. Ex-situ surface analysis of the LiNi0.5Mn1.5O4 by X-ray photoelectron spectroscopy (XPS) reveals the presence of a borate based passivating layer which appears to inhibit electrolyte oxidation on the cathode surface.

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Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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