Synergistic Effects of Li3InCl6/VGCF Composite Coating on the Electrochemical Performance of Single-Crystalline LiNi0.6Co0.1Mn0.3O2 Cathodes for All-Solid-State Lithium Batteries

Abstract

In this study, we proposed a Li3InCl6 (LIC)/vapor-grown carbon fiber (VGCF) composite coating on single-crystalline LiNi0.6Co0.1Mn0.3O2 (SC-NCM613) via a two-step liquid-phase process, targeting simultaneous enhancement of ionic and electronic transport at the cathodeelectrolyte interface. X-ray diffraction (XRD), Rietveld refinement, high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS) and Ni K-edge X-ray absorption spectroscopy (XAS) to confirm the formation of a uniform rock-salttype LIC shell intimately connected with a 2 wt.% VGCF network coating on SC-NCM613. This hybrid coating not only provided both electronic/ionic transport network but also effectively suppressed H2→H3 tetrahedral distortions of SC-NCM613 and its irreversible surface oxygen loss during cycling. Under 0.1 C cycling at 55 °C between 2.7 V and 4.3 V, the optimally loaded NCM@2VGCF@30LIC electrode retains 80.9% of its initial capacity after 50 cycles, with a Coulombic efficiency exceeding 99% and minimal voltage polarization (ΔV = 0.056 V). These findings demonstrated that LIC/VGCF composite coatings represented a promising strategy to stabilize high-voltage NCM cathodes in sulfide-based all-solid-state batteries.