Volume 41: Energy Transitions toward Carbon Neutrality: Part IV

Enhancing Electrochemical Performance of Ni-rich Cathode by Utilizing Organic Anhydride Cathode Additive Yongkang Han, Yingchuan Zhang, Yike Lei, Jie Ni, Cunman Zhang, Qiangfeng Xiao

Abstract

Ni-rich LiNixMnyCo1−x−yO2 (x ≥ 0.8) cathode is widely applied in high-end vehicle for its relatively high specific capacity and operating potential, which receives extensive attention in academia and industry. However, poor cycling performance and high cost hinder its further applications in lithium-ion batteries. In this work, 2-Methylenesuccinic anhydride is utilized as a functional cathode additive. Through the interaction between low valence Ni ions and anhydride, the facile approach allows functional 2-Methylenesuccinic anhydride more precisely work at the interface. As the operation potential rises, 2-Methylenesuccinic anhydride is oxidized prior to the electrolyte and a robust CEI layer rich in carbon oxygen double bond is built in the surface of cathode particles upon cycling, which has been analyzed by TEM and XPS. Besides, 2-Methylenesuccinic anhydride can absorb the trace of water in the cathode and electrolyte. As a result, the 0.5wt% 2-Methylenesuccinic anhydride modified NCM sample retains 91.6 % of initial capacity after charge-discharge 400 cycles at 2C. The novel modification strategy by adding a cathode additive is of important significance for mitigating deleterious side reactions in the interface for Ni-rich NCM materials.

Keywords high energy density cathode, energy storage, lithium ion batteries, organic anhydride, energy systems, Ni-rich cathode materials