Cathode-anode reaction products interplay enabling high performance of LiNi0.8Co0.1Mn0.1O2/artificial graphite pouch batteries at elevated temperature

LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) cathode coupling with artificial graphite (AG) is a promising tendency for high-energy-density batteries. However, realization of long-term lifespan under current realistic conditions remains a “Gordian knot” for large-scale commercialization-oriented realm owing to the aggressive and highly reactive Ni 4+ sites on the delithiated cathodes and electrolyte exhaustion. Vinylene carbonate (VC) is commonly employed as the additive for graphite anode in carbonate electrolytes. However, VC has limited protection ability for NCM811/AG, especially for high-temperature cycling, showing conspicuous gas generation and large interfacial resistance. Herein, advanced carbonate-based electrolytes containing vinylene carbonate (VC) and phosphate compounds like triallyl phosphate (TPPC2) and tripropargyl phosphate (TPPC3) as electrolyte additives are reported to improve the performance of NCM811/AG pouch cells at elevated temperature. Theoretical calculations and comprehensive characterizations reveal that these two electrolytes well regulate the electrodes interface with more robust and homogenous films. Moreover, the TPPC2 and TPPC3 additives exhibit stronger tendency to eliminate the corrosive active oxygen ( 1 O 2 ) released from NCM811. These merits mitigate the electrolyte decomposition, decrease the gas generation, inhibit the dissolution of transition metals from cathode, and protect the structure stability of NCM811. Such outstanding electrochemical performance reveals promising prospects in the commercialized application of NCM811/AG batteries. ● Advanced carbonate electrolyte is prepared with VC and unsaturated phosphate. ● VC and unsaturated phosphate are beneficial for generating polymer-rich CEI. ● Capacity retention of NCM811/AG cells is 90.5% after 500 cycles at 1.0 C and 55 °C. ● DEMS is used to investigate gas evolution from a new perspective.