Stabilizing LiNi0.9Mn0.1O2 structure by Al3+ doping for cobalt-free lithium-ion batteries

Abstract

Due to the scarcity and high cost of cobalt resources, the development of cobalt free batteries is considered to be the next stage of power battery research. Layered LiNi0.9Mn0.1O2 has higher energy density and better magnification performance with good prospects. However, its fragile structural stability and surface interface problems result in inferior cycle performance and rate capability compared to cobalt-containing cathode materials with the same Ni content. In this study, low magnetic resistance Al3+ is used as a doping element to enhance the structure of the material and inhibit Li/Ni disordering. As expected, The Ni-rich, Co-free cathode material doped with 2 mol% Al3+ showed the best structure and interface stability, exhibiting a capacity of 166.1 mAh·g−1 at a rate of 1 C after 180 cycles in the voltage range of 2.7–4.3 V, which was higher than that of untreated LiNi0.9Mn0.1O2 and other materials with Al3+ doping. Al3+ doping enhanced the material's rate and cycle performance. Cycling at an ultra-high rate of 5 C, the capacity retention rate reaches 86.4% after 100 cycles. The effectiveness of the modified method has been demonstrated in this study, providing a theoretical basis for the commercialization of the material to some extent.