Enhanced Electrochemical Performance of Ultrahigh Nickel Layered Oxides via Nb-Doping and Radial Order Structural Modification

Abstract

The significance of high-nickel layered oxides in lithium-ion batteries is self-evident, with LiNi 0.92 Co 0.05 Mn 0.03 O 2 (NCM9253) emerging as a promising candidate for high-energy-density batteries. Enhancing its cycling stability and rate capability is crucial for promoting the widespread adoption of electric vehicles and improving the user experience of portable devices. Here, employing density functional theory (DFT), it has been established that Nb preferentially incorporates into the bulk phase of the material. This discovery enables the rational design and preparation of NCM9253's cathode via a dual-modification strategy involving Nb doping and structural modulation, with the goal of achieving Nb doping and radial ordering. Optimal Nb 2 O 5 doping at 1 mol % resulted in a capacity retention of NCM9253 increasing from 71.2 to 102.6% after 100 cycles at 1C, with a capacity of 179.8 mAh•g −1 . Additionally, the 1 mol % Nb-doped sample exhibited enhanced rate capability, delivering 172.5 mAh•g −1 at 5C compared to the pristine sample's 146.2 mAh•g −1 . Such pronounced electrochemical improvements are attributed to strengthened structural stability facilitated by Nb−O bonding and radial ordering. This study provides new insights and experimental evidence for the design of lithium-ion battery cathode materials, thereby advancing the theoretical and practical applications of electrochemical energy storage technologies.