Phosphorus-Containing C₉H₂₁P₃O₆ Molecules as an Electrolyte Additive Improves LiNi_0.8Co_0.1Mn_0.1O₂/Graphite Batteries Working in High/Low-Temperature Conditions

LiNi_0.8Co_0.1Mn_0.1O₂ has a higher capacity but has inferior cycle stability, especially at high and low temperatures. In this work, 1-propylphosphonic acid cyclic anhydride (PACA) is designed as a functional additive of electrolyte for increasing the rate performance and long cycle stability of the LiNi_0.8Co_0.1Mn_0.1O₂/graphite full cell. Additive PACA helps to form interface films on both electrodes and a stable electrode–electrolyte interface to reduce the dissolution of the transition metal of the cathode materials and prevent the parasitic interfacial reactions of LiNi_0.8Co_0.1Mn_0.1O₂. Compared with the baseline electrolyte, these batteries with additive PACA exhibit higher capacity retention and excellent rate performance within a voltage range of 2.75–4.2 V. The batteries with 0.5 wt % additive PACA under a current density of 1 C have a capacity retention of 92% after 550 cycles at room temperature. It especially demonstrates excellent electrochemical performance (a capacity retention of 87% after 350 cycles) at high and low temperatures (45 and −20 °C), and the discharge capacity retained 51.2% theoretical capacity at 1 C.