Achieving the Interface Stability of LiMn₂O₄ Cathode Using Aqueous Polyacrylic Acid/acrylate Copolymer and Nanoscale CaCO₃ to Improve the High-Temperature Cycling and Storage Performance of Lithium-Ion Batteries

Based on a strategy of stabilizing the LiMn2O4 (LMO) cathode interface, the high-temperature cycling and storage performance of 18 650-type LMO/graphite lithium-ion batteries (LIBs) is effectively improved. The LMO cathode is prepared using lithium carboxymethyl cellulose (CMCLi)-polyacrylic acid/acrylate copolymer composite binder and nanoscale CaCO3 functional component (marked as binder C). Compared with the traditional oily binder, the dissolution of Mn2+ from LMO cathode into the electrolyte can effectively decrease, and the structure stability of LMO cathode can increase. The batteries exhibit retention capacity of 80.3% at 1 C after 600 cycles at room temperature and 76.7% at 1 C after 200 cycles at temperature of 45 degrees C. The high-temperature storage performance is also improved and there are 81.1% and 73.5% residual capacities when the fully charged batteries are stored in 60 degrees C for 14 and 28 days. The enhanced performance is mainly attributed to the interfacial stability of LMO cathode due to the bonding ability of composite binders and the elimination of HF by CaCO3. These results reveal the application prospect of as-developed aqueous binders and provide a way to improve the performance of LMO-based LIBs through stable interface strategy.