Safety-Reinforced Succinonitrile-Based Electrolyte with Interfacial Stability for High-Performance Lithium Batteries

5 years ago

Safety-Reinforced Succinonitrile-Based Electrolyte with Interfacial Stability for High-Performance Lithium Batteries

Qingqing Zhang, Xingjiang Liu, Kai Liu, Wei Li, Jinli Zhang, Fei Ding

Different contents of fluoroethylene carbonate (FEC) as cosolvent is added into succinonitrile (SN) solution to form a novel electrolyte for lithium batteries. The SN-based electrolyte with 20 wt % FEC exhibits the most favorable properties involving the good thermal stability, wide electrochemical window and high ionic conductivity. Comparing with the commercial electrolyte, the 20% FEC-SN electrolyte demonstrates the advantage of high safety and excellent interfacial compatibility with lithium due to the form of compact and smooth solid electrolyte interphase layer on the anode. LiCoO₂/Li cells using the SN-based electrolyte behave a high reversible discharge capacity of 122.4 mAh g^–1 and keep an outstanding capacity retention of 91% (122.1 mAh g^–1) at 0.5 C after 100 cycles at 25 °C, 50 °C, respectively. More importantly, the soft-package cells with the SN-based electrolyte can withstand harsh surroundings at 120 °C for 30 min without gas emitted, and can still keep the capacity retention of 77% compared to that before heat treatment, significantly higher than traditional commercial electrolyte (0%). All above results indicate the novel SN-based electrolyte can be an excellent alternative electrolyte in a practical lithium battery.

Publisher URL: http://dx.doi.org/10.1021/acsami.7b09119

DOI: 10.1021/acsami.7b09119