Modification of suitable electrolytes for high-voltage lithium-rich manganese-based cathode with wide-temperature range

Nowadays, the high-voltage cathode materials have been gradually developed, of which the lithium-rich manganese-based cathode materials (LRM) can reach more than 5.0 V (vs. Li+/Li), but there are very few electrolytes matched with the LRM. Herein, we have designed a modified electrolytes containing FEC and LiDFOB additives which has a high oxidation potential beyond 5.0 V (vs. Li+/Li), which perfectly matches the LRMs. When FEC and LiDFOB were added to the basic electrolyte, at 25 and 40 °C, the LRM has excellent cycling stability in the voltage range of 2.5–5.0 V. The capacity retention rate of the LRM/Li battery after 200 cycles was 66.5% at 25 °C, and 68.7% after 100 cycles at 40 °C. The first cycle discharge specific capacity of each system exceeds 200 mAh/g. In contrast, the capacity retention rate of lithium-ion batteries using basic electrolytes is merely 53.6 and 67.6% after cycling at 25 and 40 °C. In this work, the modified electrolytes can perfectly match the LRM at the high temperature and voltage.