Energy Storage Science and Technology ›› 2020, Vol. 9 ›› Issue (2): 346-352.doi: 10.19799/j.cnki.2095-4239.2020.0021

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Synthesis and performance of P2-O3 composite-phase Li-rich Mn-based cathode materials

ZHANG Jianyu1, LU Liping1, YU Zhihui1, SONG Jin2, XIA Dingguo2()   

  1. 1. Beijing University of Technology, Beijing 100124, China
    2. Peking University, Beijing 100871, China
  • Received:2020-01-08 Revised:2020-02-07 Online:2020-03-05 Published:2020-03-15
  • Contact: Dingguo XIA E-mail:dgxia@pku.edu.cn

Abstract:

To solve the common issues of voltage decay, low initial coulombic efficiency, and poor rate performance that occur in high-energy lithium-rich cathode materials, a P2-O3 composite-phase cathode material was synthesized by the simple solid-state method. During the first charging and discharging process, this material experienced P2-O2 phase transition, and the O2 phase prevented transition metal migration; thus, voltage decay was effectively mitigated. This P2-O3 composite-phase cathode material delivered a specific capacity of over 290 mA·h/g with an initial coulombic efficiency of 97% under a current density of 0.1C (1C = 200 mA/g) at 2.0—4.6 V. When charged at 200 mA/g, this material released a capacity of about 240 mA·h/g. After 100 cycles, the capacity retention was approximately 80% and the voltage loss was less than 170 mV. This material is easy to synthesize. At 2.0—4.6 V, it delivered a capacity as high as that of traditional lithium-rich materials tested at 2.0—4.8 V, which greatly promotes the adaptation of lithium-rich materials with commercial electrolytes. Furthermore, the cycle performance is relatively optimum and the voltage decay is suppressed to some extent, which strongly promotes the practical application of lithium-rich materials in the electric vehicles market.

Key words: composite phase, Li-rich Mn-based cathode material, voltage decay, initial coulombic efficiency

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