Self-Regulating Organic Polymer Coupled with Enlarged Inorganic SnS2Interlamellar Composite for Potassium Ion Batteries

Tin (Sn)-based alloy SnS(2)has attracted significant attention as a promising candidate for potassium ion storage due to the high theoretical capacity, however, it seriously suffers from the huge volume variation and the growth of potassium dendrites during the repeated cycling process. Herein, hierarchical polyaspartic acid (PASP) modified SnS(2)nanosheets embedded into hollow N doped carbon fibers (CN) derived from setaria glauca (PASP@SnS2@CN) are fabricated for potassium storage. PASP cross-linkers provide the enlarged interlamellar spacing of 6.8 angstrom (against 5.9 angstrom for the pristine SnS2), the higher ion transportation channels as well as the self-regulating dendrite-free K plating. Consequently, a high reversible capacity (564 mAh g(-1)at 50 mA g(-1)) and a prominent rate performance of 273 mAh g(-1)at 2 A g(-1)are delivered. Both the experimental data and computational models confirm that a thin and robust solid electrolyte interface (SEI) layer is formed over the dendrite free PASP@SnS2@CN due to the strong interactions (K-N and H+/K(+)proton exchange) between the PASP and the electrolyte (KFSI). The deformable and self- regulating organic-inorganic configuration is promising for the basis construction of transition metals, has practical applications for K storage.