Enhancing cycling stability by promoting high-voltage structural reversibility in high-nickel positive electrode...

Cycling stability remains a critical challenge in the development of high-nickel positive electrode materials for lithium-ion batteries. Although existing strategies such as delaying the formation of the H3 phase or operating below a cut-off voltage have shown promise, they limit the exploitation of the full energy density. In this study, we introduce nanorod high-nickel materials, including LiNiO₂, which demonstrate high-voltage cycling stability up to 4.95 V, more stable than traditional microcrystal counterparts. Our comparative analysis reveals that enhanced structural reversibility in the bulk structure is the key factor contributing to this improved cycling performance. The nanorod structure demonstrates an ability to endure the substantial lattice mismatch present in the Li layer at the H2-H3 interphase, thereby facilitating a comprehensive recovery from H3 to the H2 phase during discharge. This work offers insights into optimizing high-nickel positive electrode materials, improving cycling stability in high-energy battery applications.