Advanced flame-retardant electrolyte for highly stabilized K-ion storage in graphite anode

Although graphite anodes operated with representative de/intercalation patterns at low potentials are considered highly desirable for K-ion batteries, the severe capacity fading caused by consecutive reduction reactions on the aggressively reactive surface is inevitable given the scarcity of effective protecting layers. Herein, by introducing a flame-retardant localized high-concentration electrolyte with retentive solvation configuration and relatively weakened anion-coordination and non-solvating fluorinated ether, the rational solid electrolyte interphase characterized by well-balanced inorganic/organic components is tailored in situ. This effectively prevented solvents from excessively decomposing and simultaneously improved the resistance against K-ion transport.Consequently, the graphite anode retained a prolonged cycling capability of up to 1400 cycles (245 mA h g �1, remaining above 12 mon) with an excellent capacity retention of as high as 92.4%. This is superior to those of conventional and high-concentration electrolytes. Thus, the optimized electrolyte with moderate salt concentration is perfectly compatible with graphite, providing a potential application prospect for K-storage evolution. (c) 2022 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.

Automated summary

By introducing a flame-retardant localized high-concentration electrolyte, a rational solid electrolyte interphase was tailored, effectively preventing solvent decomposition and improving resistance against K-ion transport. As a result, the graphite anode exhibited prolonged cycling capability and excellent capacity retention of up to 92.4% over 1400 cycles.