Rational Electrolyte Design to Form Inorganic–Polymeric Interphase on Silicon-Based Anodes
Shaoxiong Yang, Yuping Zhang, Zhongliang Li, Norio Takenaka, Yan Liu, Hanqin Zou, Wenting Chen, Mingcong Du, Xu‐Jia Hong, Rui Shang, Eiichi Nakamura, Yue‐Peng Cai, Ya‐Qian Lan, Qifeng Zheng, Yuki Yamada, Atsuo Yamada
Abstract
Silicon-based materials have been regarded as the most promising anodes for high-energy batteries, when combined with high- voltage/capacity nickel-rich layered cathodes. However, challenges arise from unstable electrode/electrolyte interphases on the anode and cathode as well as from safety hazards associated with highly flammable commercial electrolytes. Herein, we rationally design a nonflammable cyclic phosphate-based electrolyte to tune the electrode/electrolyte interphase components by controlling the reduction of a cyclic phosphate and Li salt. This strategy enables the electrolyte to form a highly elastic, robust inorganic–polymeric interphase on microsized silicon-based anodes that can accommodate the immense volume changes. Furthermore, by generating a stable polymeric interphase on the surface of the cathode as well, a SiO|LiNi0.6Mn0.2Co0.2O2 cell demonstrated an extremely high energy density of ∼590 Wh·kg–1 with 71.4% capacity retained over 300 cycles and high Coulombic efficiency of 99.9%. This interfacial regulation strategy is of vital importance for designing new electrolytes for high-energy-density batteries.