Achieving high-voltage polymer-based all-solid-state batteries based on thermodynamic and kinetic degradation insights

Understanding the mechanisms behind the degradation in cyclic stability of polymer-based all solid-state batteries (ASSBs) at high voltages is important for facilitating their commercial application. Beyond the examination of specific material properties, from the perspectives of thermodynamic and kinetic factors, we find that the operating temperature critically influences the stability of the electrodes, electrolytes and electrode/electrolyte interfaces within the ASSBs. In this study, we constructed polymer-based ASSBs and comprehensively investigated the cyclic stability and changes in failure mechanisms with different operating temperatures at high voltages. Notably, a lower operating temperature enhanced the cyclic stability by suppressing structural collapse of the cathode and decomposition of the electrolytes while inhibiting lithium dendrites growth. The assembled lithium coin cells exhibited a superior capacity retention of 81.8% after 400 cycles at a voltage of 3.0–4.45 V and operating temperature of 40 °C. In addition, both lithium pouch cells and sodium coin cells were prepared and demonstrated excellent performances. This work provides a rational guide for the development of advanced polymer-based ASSBs. • A comprehensive understanding of the mechanisms underlying cycle degradation in polymer-based all solid-state batteries (ASSBs) at high voltages is proposed from thermodynamic and kinetic factors. • Temperature plays a critical role in influencing the cathode, cathode/all solid-state polymer electrolyte (ASPE) interface, ASPEs themselves and anode/ASPE interface. • Proper temperatures significantly enhance cycle stability of high-voltage ASSBs by preventing oxygen loss from the cathode, reducing side reactions at electrode/ASPE interfaces, and inhibiting lithium dendrite growth.