Rational design of electrode mesostructures with integration of polycrystalline and single-crystalline Ni-rich particles

Abstract

Achieving high areal capacity in cathode electrodes is indispensable for the commercial realization of highenergy-density lithium-ion batteries (LIBs). However, such thick and dense cathode electrodes often suffer from sluggish kinetics, particle fracture, and nonuniform electrochemical reactions within the electrode, ultimately leading to battery degradation. Herein, we tailored a bimodal electrode architecture by integrating commercially viable Ni-rich single-crystalline LiNi0.8Co0.1Mn0.1O2 (SC-NCM) and polycrystalline NCM (PC-NCM) to resolve this trade-off. We demonstrate that smaller SC-NCM particles perform crucial dual functions. They not only function as interstitial fillers to improve packing density and spatial uniformity across the electrode, but also serve as mechanical buffers to dissipate stress concentrations and preserve the structural integrity of the fragile PC-NCM framework during high-pressure calendering. This synergistic architecture results in a significant reduction of electrode resistance, which in turn improves rate capability and enhances high-temperature cycling stability, despite utilizing the same active material chemistry. This work proves that engineering material-level architecture is a powerful strategy for overcoming the performance limitations of current materials, providing practical guidance for designing high-energy-density LIBs.