High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries. However, the poor structural stability and severe side reactions at the electrode/electrolyte interface result in unsatisfactory cycle performance. Herein, the thin layer of two-dimensional (2D) graphitic carbon-nitride (g-C₃N₄) is uniformly coated on the LiNi_0.8Co_0.1Mn_0.1O₂ (denoted as NCM811@CN) using a facile chemical vaporization-assisted synthesis method. As an ideal protective layer, the g-C₃N₄ layer effectively avoids direct contact between the NCM811 cathode and the electrolyte, preventing harmful side reactions and inhibiting secondary crystal cracking. Moreover, the unique nanopore structure and abundant nitrogen vacancy edges in g-C₃N₄ facilitate the adsorption and diffusion of lithium ions, which enhances the lithium deintercalation/intercalation kinetics of the NCM811 cathode. As a result, the NCM811@CN-3wt% cathode exhibits 161.3 mAh g⁻¹ and capacity retention of 84.6% at 0.5 C and 55 ℃ after 400 cycles and 95.7 mAh g⁻¹ at 10 C, which is greatly superior to the uncoated NCM811 (i.e. 129.3 mAh g⁻¹ and capacity retention of 67.4% at 0.5 C and 55 ℃ after 220 cycles and 28.8 mAh g⁻¹ at 10 C). The improved cycle performance of the NCM811@CN-3wt% cathode is also applicable to solid–liquid-hybrid cells composed of PVDF:LLZTO electrolyte membranes, which show 163.8 mAh g⁻¹ and the capacity retention of 88.1% at 0.1 C and 30 ℃ after 200 cycles and 95.3 mAh g⁻¹ at 1 C.

For next-generation all-solid-state metal batteries, the computation can lead to the discovery of new solid electrolytes with increased ionic conductivity and excellent safety. Based on computational predictions, a new proposed solid electrolyte with a flat energy landscape and fast ion migration is synthesized using traditional synthesis methods. Despite the promise of the predicted solid electrolyte candidates, conventional synthetic methods are frequently hampered by extensive optimization procedures and overpriced raw materials. It is impossible to rationally develop novel superionic conductors without a comprehensive understanding of ion migration mechanisms. In this review, we cover ion migration mechanisms and all emerging computational approaches that can be applied to explore ion conduction in inorganic materials. The general illustrations of sulfide and oxide electrolyte structures as well as their fundamental features, including ion migration paths, dimensionalities, defects, and ion occupancies, are systematically discussed. The major challenges to designing the solid electrolyte and their solving strategies are highlighted, such as lattice softness, polarizability, and structural disorder. In addition to an overview of recent findings, we propose a computational and experimental approach for designing high-performance solid electrolytes. This review article will contribute to a practical understanding of ion conduction, designing, rapid optimization, and screening of advanced solid electrolytes in order to eliminate liquid electrolytes.