All-solid-state lithium batteries with NMC955 cathodes: PVDF-free formulation with SBR and capacity recovery insights

The nickel-rich NMC₉₅₅ (LiNi_0.90Mn_0.05Co_0.05O₂) cathode, with minimal cobalt, is the zenith of NMC technology but faces structural and thermal stability challenges, losing an average of 15 % of its capacity in the first discharge. Here, by selecting appropriate materials and synthesis methods in an all-solid-state battery cell, this challenge is effectively mitigated. A sustainable fabrication of the LiNMC₉₅₅ positive electrode, excluding PVDF and using styrene-butadiene rubber SBR, demonstrates high retention in all-solid-state cells, without additional interlayers or pressure, at room temperature. To prevent oxygen release, spurious phase formation, and magnetic frustration, simulations determined optimal cycling thresholds and curve morphologies for a Li⁰/Li₆PS₅Cl/NMC₉₅₅ cell by “following the electrons”. This optimized routine ensures prolonged cycle life and performance demonstrated by sheet resistance/Hall effect, SEM/EDX, AFM/SKPM, TOF-SIMS, Raman, calorimetry, and electrochemical analyses. The tailored preparation method and cycling regimen enabled the fabrication of a high-performance cathode, achieving capacities exceeding 110-120 mAh.g^-1 at C discharging C-rate, after 200 cycles, with a self-recovering component shifting performance to theoretical capacities (192 mAh.g^-1), emphasizing the cathode's pivotal role in all-solid-state performance.