A critical challenge for the commercialization of layer-structured nickel-rich lithium transition metal oxide cathodes for battery applications is their capacity and voltage fading, which originate from the disintegration and lattice phase transition of the cathode particles. The general approach of cathode particle surface modification could partially alleviate the degradation associated with surface processes, but it still fails to resolve this critical barrier. Here, we report that infusing the grain boundaries of cathode secondary particles with a solid electrolyte dramatically enhances the capacity retention and voltage stability of the cathode. We find that the solid electrolyte infused in the boundaries not only acts as a fast channel for lithium-ion transport, it also, more importantly, prevents penetration of the liquid electrolyte into the boundaries, and consequently eliminates the detrimental factors, which include cathode–liquid electrolyte interfacial reactions, intergranular cracking and layered-to-spinel phase transformation. This grain-boundary engineering approach provides design ideas for advanced cathodes for batteries.

对于用于电池应用的层状结构的富镍的锂过渡金属氧化物阴极的商业化而言，关键的挑战是它们的容量和电压衰减，其源自阴极颗粒的崩解和晶格相变。阴极粒子表面改性的一般方法可以部分缓解与表面过程相关的降解，但仍无法解决这一关键障碍。在这里，我们报告说，用固体电解质注入阴极次级颗粒的晶界会显着提高阴极的容量保持率和电压稳定性。我们发现注入边界的固体电解质不仅充当锂离子运输的快速通道，而且更重要的是，防止液体电解质渗入边界，从而消除有害因素，包括阴极-液体电解质界面反应，晶间裂纹和层状至尖晶石相变。这种晶界工程方法为电池高级阴极提供了设计思路。