Progressive concentration gradient nickel-rich oxide cathode material for high-energy and long-life lithium-ion batteries

Abstract

Nickel-rich layered transition-metal oxides with high reversible capacity are considered the most promising cathode candidates for next-generation LIBs. However, their applications are limited by an insufficient cycle life that originates from structural instability. To address this issue, a novel progressive concentration gradient cathode material (LiNi_0.7Co_0.13Mn_0.17O₂) was successfully synthesized that exhibits a progressively increasing transition metal evolution rate from core to surface within peer microsized spherical particle. Importantly, this material achieved a reasonable transition metal distribution to effectively alleviate internal stress and improve the structural stability of cathode particles upon cycling. Meanwhile, the average Ni content was maximized while maintaining a high-stability Mn/Co-rich surface. Consequently, the progressive concentration gradient cathode material delivered superior reversible capacity (189.9 mA h g⁻¹ at 3.0–4.3 V) and cycling stability (86.5% capacity retention after 300 cycles at 1C), providing a novel method to obtain promising high-performance cathode materials to satisfy growing demand for future electric vehicles.