Structural self-reconstruction strategy empowering Ni-rich layered cathodes with low-strain for superior cyclabilities
Zhouliang Tan, Yunjiao Li, Xiaoming Xi, Shijie Jiang, Xiaohui Li, Xingjie Shen, Panpan Zhang, Zhenjiang He
Abstract
The key to hindering the commercial application of Ni-rich layered cathode is its severe structural and interface degradation during the undesired phase transition (hexagonal to hexagonal (H2 → H3)), degenerating from the build-up of mechanical strain and undesired parasitic reactions. Herein, a perovskite Li0.35La0.55TiO3 (LLTO) layer is built onto Ni-rich cathodes crystal to induce layered@spinel@perovskite heterostructure to solve the root cause of capacity fade. Intensive exploration based on structure characterizations, in situ X-ray diffraction techniques, and first-principles calculations demonstrate that such a unique heterostructure not only can improve the ability of the host structure to withstand the mechanical strain but also provides fast diffusion channels for lithium ions as well as provides a protective barrier against electrolyte corrosion. Impressively, the LLTO modified LiNi0.9Co0.05Mn0.05O2 cathode manifests an unexpected cyclability with an extremely high-capacity retention of ≈ 94.6% after 100 cycles, which is superior to the pristine LiNi0.9Co0.05Mn0.05O2 (79.8%). Furthermore, this modified electrode also shows significantly enhanced cycling stability even withstanding a high cut-off voltage of 4.6 V. This surface self-reconstruction strategy provides deep insight into the structure/interface engineering to synergistically stabilize structure stability and regulate the physicochemical properties of Ni-rich cathodes, which will also unlock a new perspective of surface interface engineering for layered cathode materials.