Combinational Intercalation-Conversion-Intercalation reaction of CuInS2@PPy anode for Sodium-Ion batteries.

As an anode for sodium-ion batteries, CuInS 2 @PPy exhibits excellent rate performance and cycling stability due to the synergism of combinational intercalation-conversion-intercalation reaction mechanism and the high conductivity of the PPy coating layer. [Display omitted] Polypyrrole-coated CuInS 2 (CuInS 2 @PPy) composite was prepared through the chemical vapor transport method and subsequent in situ polymerized coating strategy. In this unique nanoarchitecture, the PPy coating layer plays a crucial role in improving the conductivity of the composite, suppressing the volume change of CuInS 2 , and maintaining the structural integrity of electrode material upon cycling. In addition, the electrochemical reaction mechanism and kinetics of CuInS 2 @PPy were investigated in-depth. Benefitting from the synergism of its combinational intercalation-conversion-intercalation reaction mechanism and the high conductivity of the PPy coating layer, CuInS 2 @PPy electrode exhibits superior rate capability and cycling stability for sodium-ion batteries, with a capacity of 404.8 mA h g−1 at 4 A g−1 over 2500 cycles. [ABSTRACT FROM AUTHOR]