Stress‐Relieving Protective Elastomeric Interphase for Stable Ni‐rich Cathodes

Anisotropic volume changes in primary particles of layered Ni‐rich transition metal oxides generate mechanical stresses during electrochemical cycling. This results in structural degradation and side reactions that deteriorate battery performance. To address this issue, a cross‐linked epoxy natural rubber (CENR) is employed as the protective elastomeric interphase. The viscoelastic properties of CENR facilitated a strong adhesion to the surface of Ni‐rich cathodes, thereby helping alleviate mechanical stresses during cycling. This approach maintained the structural integrity of the Ni‐rich cathodes and suppressed detrimental interfacial reactions. Consequently, the fortified Ni‐rich cathode retained 95.9% of its capacity after 300 cycles at 0.5 C and 82.8% after 500 cycles at 1 C. This study highlights the essential role of elastomeric materials in stabilizing Ni‐rich cathodes and offers insights that can enable the development of additional protective elastomeric layers for battery electrode materials.