Regulating and understanding the compatibility of sulfide composite solid-state electrolyte in nickel-rich lithium metal batteries

In the pursuit of high-energy-density lithium batteries, composite solid-state electrolytes are highly favored due to the combination of flexibility and acceptable ionic conductivity. However, challenges such as unpredictable lithium dendrite growth, cathode material structural instability, and oxidative resistance at high voltages pose significant hurdles for solid-state batteries. To investigate the synergistic interactions of polymers and sulfides, a hybrid poly (1,3-dioxolane) and poly (polyethylene glycol diacrylate) blend was designed through in-situ polymerization, allowing LiFePO4//Li batteries to achieve an average coulombic efficiency exceeding 99% at 0.5C and stable cycling for at least 1000 h in lithium symmetric cells. Computational analysis and component detection demonstrate the stability of the components and the formation of a LiF-stabilized anode from lithium salt decomposition. Similarly, on the cathode side, when Li3PO4-coated LiNi0.6Co0.2Mn0.2O2 is used as the cathode material, a more stable interface suppresses cathode particles' collapse and harmful electrolytes' decomposition. In ambient environments, after 200 cycles at 0.5C, the capacity retention remains as high as 90.48%. Impedance changes by in-situ methods and component composition were further analyzed. This work integrates multiple methods and stabilizes and validates the anode and cathode interface, providing a promising approach and strategy for designing high-performance sulfide composite solid-state batteries.