High-Voltage-Resistant Highly Stable Solid Polymer Electrolyte via In Situ Integrated Construction with Fast Ion Migration

Electric aircraft such as electric aircraft and electric vehicles play a key role in the future electric aviation industry, but they put forward huge requirements for battery energy density. However, the current high-energy-density lithium battery technology still needs to be broken through. Herein, through the molecular structure design of the polymer electrolyte, a strategy of a fast migration channel and wide electrochemical window is proposed to fabricate high-voltage-resistant solid polymer electrolyte (HVPE) via in situ polymerization. Thus, HVPE exhibits an ultrahigh Li⁺ transfer number (t_Li+) of 0.92 and an excellent electrochemical window of 5.1 V to match with a high-voltage lithium cobalt oxide (LCO) cathode. This fast conduction of Li+ allows for stable and uniform lithium plating and stripping deposition for more than 1000 h, which also reveals a well-defined dual interfacial stabilization mechanism. These results endow the assembled LCO|HVPE|Li cell cycles steadily for 500 cycles at 4.5 V and 0.5C with a superior capacity retention of 89.93%. Moreover, the assembled LCO|HVPE|Li pouch cell exhibits a capacity retention rate of up to 94.01% after 50 cycles. More importantly, our proposed HVPE provides new insights into structural design and fabrication strategies for high-energy-density solid-state polymer batteries.