Cosolvent electrolyte chemistries for high-voltage potassium-ion battery
Mengkang Shen, Zhongqin Dai, Ling Fan, Hongwei Fu, Yuanhui Geng, Jie Guan, Fanfei Sun, Apparao M. Rao, Jiang Zhou, Bingan Lu
Abstract
ABSTRACT The poor oxidation resistance of traditional electrolytes has hampered the development of high-voltage potassium-ion battery technology. Here, we present a cosolvent electrolyte design strategy to overcome the high-voltage limitations of potassium-ion electrolyte chemistries. The cosolvent electrolyte breaks the dissolution limitation of the salt through ion–dipole interactions, significantly enlarging the anion-rich solvation clusters, as verified by the insitu synchrotron-based wide-angle X-ray scattering experiments. Furthermore, the large anion-rich solvation clusters also facilitate the formation of an effective electrode–electrolyte interphase, thereby enhancing compatibility with high-voltage electrodes. The cosolvent electrolyte enables K||Prussian blue cells (2–4.5 V) to operate for >700 cycles with a capacity retention of 91.9%. Our cosolvent electrolyte design strategy paves new avenues for the development of high-voltage potassium-ion batteries and beyond.