Advanced Electrolytes for Fast‐Charging High‐Voltage Lithium‐Ion Batteries in Wide‐Temperature Range

• Published in: Advanced energy materials 2020-06, Vol.10 (22), p.n/a
• Main Authors: Zhang, Xianhui, Zou, Lianfeng, Xu, Yaobin, Cao, Xia, Engelhard, Mark H., Matthews, Bethany E., Zhong, Lirong, Wu, Haiping, Jia, Hao, Ren, Xiaodi, Gao, Peiyuan, Chen, Zonghai, Qin, Yan, Kompella, Christopher, Arey, Bruce W., Li, Jun, Wang, Deyu, Wang, Chongmin, Zhang, Ji‐Guang, Xu, Wu
• Format: Article
• Language: English
• Subjects: Cathodes; Charging; Discharge; Electrode materials; Electrolytes; high‐Ni layered cathodes; Lithium; Lithium-ion batteries; localized high‐concentration electrolytes; Oxidation; Room temperature
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202000368

LiNixMnyCo1−x−yO2 (NMC) cathode materials with Ni ≥ 0.8 have attracted great interest for high energy‐density lithium‐ion batteries (LIBs) but their practical applications under high charge voltages (e.g., 4.4 V and above) still face significant challenges due to severe capacity fading by the unstable cathode/electrolyte interface. Here, an advanced electrolyte is developed that has a high oxidation potential over 4.9 V and enables NMC811‐based LIBs to achieve excellent cycling stability in 2.5–4.4 V at room temperature and 60 °C, good rate capabilities under fast charging and discharging up to 3C rate (1C = 2.8 mA cm−2), and superior low‐temperature discharge performance down to −30 °C with a capacity retention of 85.6% at C/5 rate. It is also demonstrated that the electrode/electrolyte interfaces, not the electrolyte conductivity and viscosity, govern the LIB performance. This work sheds light on a very promising strategy to develop new electrolytes for fast‐charging high‐energy LIBs in a wide‐temperature range. Advanced localized high‐concentration electrolytes are developed to inhibit Ni dissolution and particle cracking in high‐Ni (≥0.8) LiNixMnyCo1−x−yO2 cathode materials when cycling under 4.4 V through formation of uniform, robust, and conductive electrode/electrolyte interfaces, thus enabling excellent long‐term cycling stability in a wide‐temperature range, superior fast‐charging and fast‐discharging capabilities, and superior low‐temperture performance when compared to conventional electrolytes.