Surface Microstructure Engineering for Enhancing Li-Ion Diffusion and Structure Stability of Ni-Rich Cathode Materials

TL;DR

This paper introduces a new method to improve the performance and stability of nickel-rich battery cathodes by engineering their surface structure.

Contribution

A novel surface heterojunction strategy using ZnO to enhance interfacial kinetics and structural stability in Ni-rich cathode materials.

Findings

NCA@ZnO shows 83.7% capacity retention after 160 cycles at 3 C between 3.0–4.5 V.

ZnO layer suppresses parasitic reactions and improves structural stability.

The built-in electric field from the heterojunction enhances Li-ion diffusion.

Abstract

Surface microstructure of grains vastly decides the electrochemical performance of nickel-rich oxide cathodes, which can improve their interfacial kinetics and structural stability to realize their further popularization. Herein, taking the representative LiNi0.8Co0.15Al0.05O2 (NCA) materials as an example, a surface heterojunction structure construction strategy to enhance the interface characteristics of high-nickel materials by introducing interfacial ZnO sites has been designed (NCA@ZnO). Impressively, this heterointerface creates a strong built-in electric field, which significantly improves electron/Li-ion diffusion kinetics. Concurrently, the ZnO layer acts as an effective physical barrier against electrolyte corrosion, notably suppressing interfacial parasitic reactions and ultimately optimizing the structure stability of NCA@ZnO. Benefiting from synchronous optimization of interface stability and kinetics, NCA@ZnO exhibits advanced cycling performance with the capacity retention of 83.7% after 160 cycles at a superhigh rate of 3 C during 3.0–4.5 V. The prominent electrochemical performance effectively confirms that the surface structure design provides a critical approach toward obtaining high-performance cathode materials with enhanced long-cycling stability.

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