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

The nickel-rich NMC955 (LiNi0.90Mn0.05Co0.05O2) cathode, with minimal cobalt, is the zenith of LiNixMnyCo1-x-yO2 (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 poly(vinylidene fluoride) (PVDF) and using styrene-butadiene rubber, 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, Scanning Electron Microscopy/Energy-Dispersive X-ray Spectroscopy (SEM/EDX), Atomic Force Microscopy/Scanning Kelvin Probe Microscopy, Time-of-Flight Secondary Ion Mass Spectrometry, 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.