1,3,5-Trihydroxybenzene as a film-forming additive for high-voltage positive electrode

1,3,5-trihydroxybenzene (THB) is examined as a film-forming additive for over-lithiated layered oxide positive electrode. The surface film generated from the carbonate-based electrolyte (THB-free) is thermally/electrochemically unstable to be dissolved or decomposed during elevated-temperature cycling. Due to this instability, electric charges are consumed in every cycle for electrolyte decomposition to give a low coulombic efficiency. In contrast, the protective film that is generated by oxidative decomposition of the additive (THB) prior to the carbonate electrolyte is robust enough to remain intact. As a result, a full-cell comprising graphite/over-lithiated layered oxide gives a higher coulombic efficiency and longer life cycle. (c) 2012 Elsevier B.V. All rights reserved.