Advances in modification methods and the future prospects of high-voltage spinel LiNi0.5Mn1.5O4 — a review

Abstract

In order to reduce the production cost of lithium-ion batteries and the damage to the environment, cobalt-free cathode materials have become the focus of the lithium-ion battery industry. High-voltage spinel LiNi_0.5Mn_1.5O₄ (LNMO) as an excellent cathode material has broad application prospects and huge possibility of being put into commercial production, due to its high voltage platform (∼4.7 V vs. Li), high theoretical energy density (∼650 W h kg⁻¹), low environmental impact and low cost. However, the cycle performance and high temperature stability of this cathode are terrible, hindering its large-scale production and use. Recently, numerous approaches have been devoted to improving the cycle stability of high-voltage LNMO cathodes, and some good results have been achieved, which can help us to deepen our understanding of the degradation mechanism of LNMO. In order to highlight this accomplishment and further solve the pending issues of LNMO, it is necessary to summarize the achievements obtained from these studies. In this review, we first introduce the research background, advantages and disadvantages of LNMO cathode materials; secondly, the basic principles of LNMO such as the crystal structure and discharge mechanism were analyzed; then, we discuss the recent advances in boosting the electrochemical performance of LNMO, including structural design, crystal plane regulation, doping, surface coating, etc. Finally, the further perspectives and research directions of LNMO are discussed, such as machine learning and AI-assisted virtual experiments, which provide new insight for the development of LNMO cathode materials.