Simultaneously trapping solvents molecules and anions for stable and safe potassium-ion batteries

Abstract Critical issues along with potassium-ion batteries (PIBs) lies in free organic solvents molecules are always flammable, easily oxidized and will trigger the formation of potassium dendrite during cycling, leading to severe safety concerns and deteriorated cycle stability. Here, an environmental friendliness and facile preparation zeolitic imidazolate framework electrolyte, enabled by framework trapping strategy, is proposed to improve the performance of PIBs. The low cost electrolyte with simultaneously trapping strategy possesses high ionic conductivity, high oxidative stability (over 5.9 V), diverse inhibitory abilities - K dendrites, “shuttle effect”, and organic dissolution. Consequently, potassium metal symmetric battery shows a stable operation over 5,000 h at 0.1 mA cm−2, and graphite based potassium anode exhibits high capacity retention and high Coulombic efficiency. The high-voltage vanadium fluorophosphate (cycle in 2.0-4.6 V), easily soluble 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) cathodes also can stable cycles more than 1,000 and 2,100 cycles, respectively. Moreover, the high energy density safe graphite||PTCDI based full cells exhibits an average capacity decay rate of 0.034% per cycle for 1,000 cycles at 50 mA g−1. This study presents a fresh approach for designing and developing low-cost and sustainable PIBs and beyond.