Abstract:

With prospects for high energy density and safety, all-solid-state lithium-ion batteries (ASSLBs) with lithium-rich manganese-based materials (LRMs) are exploited as next-generation energy storage systems. However, the severe interfacial degradations with halide solid electrolytes (SEs) caused by the irreversible oxygen release remain to be urgently solved. In this work, we synthesized Cr-substituted LRMs with high capacity and stability. The reversible redox of Cr³⁺/Cr⁶⁺ contributes to an enhanced capacity, accompanied by the reversible migration of Cr⁶⁺ ions between octahedral and tetrahedral sites, effectively maintaining the structural stability of LRMs. Meanwhile, the strong Cr–O bond can stabilize the lattice oxygen, establish a stable cathode/electrolyte interface, and alleviate the voltage decay. Therefore, the ASSBs with LRMs-Cr0.1 cathode and halide electrolyte show an excellent cycling stability with 0.065% capacity decay per cycle for 500 cycles at 0.5C. Notably, the LRMs-Cr0.1//Li₂₁Si₅@Si/C full cell exhibits outstanding long-term cyclability over 1000 cycles with nearly 100% capacity retention at 0.3C, corresponding to an energy density of 413.11 Wh kg⁻¹. This work provides guidance for developing high energy-density solid-state batteries.

Key words: All-solid-state battery, Lithium-rich manganese-based material, Anion oxygen redox, Chromium substitution, Li₂₁Si₅@Si/C anode