Revealing the different effects of VIB transition metals X (X = Cr, Mo, W) on the electrochemical performance of Li-rich cathode Li2MnO3 by first-principles calculations

Shiwei Zhang; Jianchuan Wang; Huan Liu; Weibin Zhang; Lixian Sun; Yong Du; Hans J Seifert; Ting Lei

doi:10.1039/d2nr04894a

Revealing the different effects of VIB transition metals X (X = Cr, Mo, W) on the electrochemical performance of Li-rich cathode Li₂MnO₃ by first-principles calculations

Nanoscale. 2022 Oct 21;14(40):15034-15047. doi: 10.1039/d2nr04894a.

Authors

Shiwei Zhang¹, Jianchuan Wang¹, Huan Liu², Weibin Zhang², Lixian Sun³, Yong Du¹, Hans J Seifert⁴, Ting Lei¹

Affiliations

¹ State Key Laboratory of Powder Metallurgy, Central South University, 410083, Changsha, China. jcw728@126.com.
² Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, 250061, Jinan, China.
³ Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology, 541004, Guilin, China.
⁴ Institute for Applied Materials, Karlsruhe Institute of Technology, Germany.

PMID: 36197320
DOI: 10.1039/d2nr04894a

Abstract

Transition metal (TM) doping is widely applied to optimize the electrochemical performance of Li₂MnO₃, a promising cathode material of next-generation Li-ion batteries. The effect of doping on the performance of Li₂MnO₃ can vary with the elemental period of the doped TM. However, the rules of the different effects have not been well summarized, especially for TM elements within the same group. In this work, the effects of TM element (Cr, Mo, and W in group VIB) dilute doping on the electrochemical performance of Li₂MnO₃ are investigated through first-principles calculations. The results show that Mo and W can induce more obvious local lattice distortion. Although Cr, Mo and W doping can improve the electrochemical activity of Li₂MnO₃, they modify the charge compensation mechanism in different ways. At the initial stage of delithiation, both Cr and O undergo significant oxidation, and Mo can act as the main oxidation center, while W can trigger the electrochemical activity of Mn around it. The O ions around Mo and W are more stable during the delithiation due to the mild oxidation and the strong bonding of Mo-O and W-O. Furthermore, Cr, Mo and W dilute doping can promote the interlayer diffusion of Li at the initial charging state, which is gradually enhanced with the increase of the period of the doped elements, but Mo and W doping would hinder the intralayer diffusion of Li near the doping sites during further delithiation process. Our results highlight the difference in the effects of TM (in the same group) doping on the performance of Li₂MnO₃ and would facilitate fast and good design of Li-rich cathodes.