Polyacrylonitrile-coated nickel-cobalt-manganese oxide cathodes for stable interfaces in solid-state batteries

초록

NCM cathodes are critical for achieving high energy density in all-solid-state batteries, yet their electrochemical stability is severely limited by interfacial degradation and mechanical incompatibilities with solid electrolytes. Despite their potential, the role of polymer-based surface engineering in addressing these interfacial challenges remains insufficiently understood. Here, through the thermal cyclization of polyacrylonitrile (PAN) and the fabrication of a poly(vinylidene fluoride-hexafluoropropylene)-based hybrid polymer electrolyte (PVDF-HFPbased HPE), we demonstrate that a dual-modification strategy significantly improves interfacial stability and charge transport. In the first stage, a conformal cyclized PAN (cPAN) coating layer forms a conductive and elastic interface on NCM, suppressing side reactions and maintaining structural integrity during cycling. Second, a LiOH-modified PVDF-HFP-based HPE provides high ionic conductivity and enhanced oxidative stability, ensuring durable electrode-electrolyte contact. Taken together, this synergistic approach delivers superior cycling stability (93.96% retention after 100 cycles) and maintains a high reversible capacity of 167.06 mAh & sdot;g-1 following rate capability evaluation up to 2 C, underscoring its promise for scalable high-performance all-solidstate batteries.

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