Unexpected Planar Gliding and Microcracking Induced by Neutron Irradiation in Single-Crystalline LiCoO2 Cathodes

Lithium-ion batteries have become increasingly vital in powering aerospace applications, where radiation resistance is a mission-critical battery property. Little is known about the effects of space irradiation on battery materials in operation, particularly neutron irradiation. Understanding the structural and electrochemical failure mechanisms of battery materials in radiation environments is thus crucial for high-performance aerospace applications. Here, we investigate LiCoO 2 (LCO) cathode degradation under simulated space radiation at the China Spallation Neutron Source. Broad-spectrum neutron exposure (ranging from meV to GeV) induces microcracks and stress in LCO crystals, impairing Li + diffusion and destabilizing the oxygen framework. Operando neutron studies reveal that capacity loss stems from irradiation-triggered interlayer planar gliding during Li de/intercalation. Finally, we show that the irradiation damage can be effectively mitigated by reducing the LCO crystalline particle size. Thus, our work provides the critical knowledge for designing radiation-resistant cathode materials for critical applications.