Submicron single-crystal structure for enhanced structural stability of LiNi0.8Mn0.2O2 Ni-rich cobalt-free cathode materials

Because of its high specific capacity and low cost, high nickel cobalt-free layered oxide is regarded as an important next-generation lithium ion cathode material. However, its commercialization is difficult due to poor cycle performance and thermal unstability. Submicron single-crystal LiNi0.8Mn0.2O2 synthesized by double jet mill has unique morphology and dispersibility, which enhances the structural stability of the material. The results show that the specific discharge capacity and initial coulombic efficiency of single-crystal submicron LiNi0.8Mn0.2O2 are obviously higher than those of polycrystalline LiNi0.8Mn0.2O2, the capacity of which is 170.5 mAh center dot g(-1) under 1 C. And the specific discharge capacity after 200 cycles is obviously higher than that of polycrystalline LiNi0.8Mn0.2O2, with the respective values under 5 C high current being 146.0 mAh center dot g(-1) and 119.3 mAh center dot g(-1). The enhancement of cycle and rate performance of single-crystal LiNi0.8Mn0.2O2 structure can be attributed to its unique morphology and stable structure, which can reduce microcracks, surface polarization, irreversible phase transition, surface side reactions, and so on. In addition, the submicron single-crystal LiNi0.8Mn0.2O2 has a lower Ni2+/Li+ cation mixing and a shorter Li+ diffusion migration path, which contributes to the improvement of rate performance.