Article ID Journal Published Year Pages File Type
218190 Journal of Electroanalytical Chemistry 2015 6 Pages PDF
Abstract

•High-temperature capacity fading for LiFePO4/graphite soft-packed cell was studied.•Temperature-dependent extent of surface structural disorder in graphite was found.•Active lithium loss is still a dominating mechanism for irreversible capacity loss.•Fast and continuous reformation/repairing mechanism of instable SEI was proposed.

Commercial electrolyte containing functional additives that completely suppress Fe dissolution from the LiFePO4 electrode was used in LiFePO4/graphite soft-packed cell for eliminating its catalysis to solid electrolyte interphase (SEI) formation. The results show that the cycle performances of assembled soft-packed full-cell were still temperature-dependent. Average Raman spectra show temperature-dependent extent of surface structural disorder in graphite, leading to higher interfacial resistance at elevated temperatures. Half-cell studies using cycled cathode at different temperatures reveal different lithiated LixFePO4. An accelerated mechanism of the operating temperature to reformation/repairing of SEI layer is proposed, which greatly consumes active lithium during cycling, therefore causes fast capacity loss at elevated temperatures.

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Physical Sciences and Engineering Chemical Engineering Chemical Engineering (General)
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