Mitigating Voltage Decay of Li-Rich Cathode Material via Increasing Ni Content for Lithium-Ion Batteries

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• 作者：Ji-Lei Shi ; Jie-Nan Zhang ; Min He ; Xu-Dong Zhang ; Ya-Xia Yin ; Hong Li ; Yu-Guo Guo ; Lin Gu ; Li-Jun Wan
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：August 10, 2016
• 年：2016
• 卷：8
• 期：31
• 页码：20138-20146
• 全文大小：653K
• 年卷期：0
• ISSN：1944-8252

文摘

Li-rich layered materials have been considered as the most promising cathode materials for future high-energy-density lithium-ion batteries. However, they suffer from severe voltage decay upon cycling, which hinders their further commercialization. Here, we report a Li-rich layered material 0.5Li₂MnO₃·0.5LiNi_0.8Co_0.1Mn_0.1O₂ with high nickel content, which exhibits much slower voltage decay during long-term cycling compared to conventional Li-rich materials. The voltage decay after 200 cycles is 201 mV. Combining in situ X-ray diffraction (XRD), ex situ XRD, ex situ X-ray photoelectron spectroscopy, and scanning transmission electron microscopy, we demonstrate that nickel ions act as stabilizing ions to inhibit the Jahn–Teller effect of active Mn³⁺ ions, improving d–p hybridization and supporting the layered structure as a pillar. In addition, nickel ions can migrate between the transition-metal layer and the interlayer, thus avoiding the formation of spinel-like structures and consequently mitigating the voltage decay. Our results provide a simple and effective avenue for developing Li-rich layered materials with mitigated voltage decay and a long lifespan, thereby promoting their further application in lithium-ion batteries with high energy density.