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 LiNi_0.6Co_0.1Mn_0.3O₂ (SC-NCM613) via a two-step liquid-phase process, targeting simultaneous enhancement of ionic and electronic transport at the cathode–electrolyte 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) confirmed the formation of a uniform rock-salt-type LIC shell intimately connected with a 2 wt% VGCF network coating on SC-NCM613. This hybrid coating not only provided both the electronic/ionic transport network but also effectively suppressed H2 → H3 tetrahedral distortions of SC-NCM613 and its irreversible surface oxygen loss during cycling. Under 0.1C cycling at 55 °C between 2.7 V and 4.3 V, the optimally loaded NCM@2VGCF@30LIC electrode retained 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 represent a promising strategy to stabilize high-voltage NCM cathodes in sulfide-based all-solid-state batteries.