Enhanced LiMn0.8Fe0.2PO4 Cathode Performance Enabled by the 1,3,2-Dioxathiolane-2,2-dioxide Electrolyte Additive

Engineering the electrode/electrolyte interface through the addition of electrolyte additives has proven to be a promising strategy for enhancing the cell performance, and there are distinguishable discrepancies in the effect of 1,3,2-dioxathiolane-2,2-dioxide (DTD) as an electrolyte additive in different cell systems. Herein, DTD is added into the electrolyte for the Li/LiMn0.8Fe0.2PO4 cell and its functions on the LiMn0.8Fe0.2PO4 cathode are studied. The result demonstrates that a beneficial effect on the LiMn0.8Fe0.2PO4 performance is generated by adding DTD into the electrolyte, which is attributed to the decreased products arising from the interfacial side reactions on the surface of the LiMn0.8Fe0.2PO4 cathode and the reduced metal dissolution in the electrolyte because of the easier and stronger binding between DTD and PF6– and the prioritized oxidation of DTD. The addition of DTD increased the capacity retention of the LiMn0.8Fe0.2PO4 cathode from 46.52 to 70.54% after 1000 cycles at 1 C over the voltage range of 3.0–4.5 V. Therefore, DTD is rendered as an effective electrolyte additive for engineering the cathode/electrolyte interface in favor of enhancing the performance of LiMn0.8Fe0.2PO4, providing a facile interfacial strategy to enhance the performance of LiMnPO4-based cathodes.