Nickel Single‐Atoms Modified Organic Anodes with Enhanced Reaction Kinetics for Stable Potassium‐Ion Batteries

Abstract

AbstractThe redox‐active organic compounds including potassium 1,1′‐biphenyl‐4,4′‐dicarboxylate (K‐BPDC) are attracting considerable attention as anodes for potassium‐ion batteries (PIBs). Nevertheless, the practical applications of K‐BPDC organic anodes are severely hindered by short cycle life due to their relatively sluggish redox kinetics and instability. In this work, Ni single atoms (up to 6 wt.%) are implanted into K‐BPDC (NiSA@K‐BPDC) by using an electrochemical‐induced reconstruction (EIR) strategy to enhance the reaction kinetics and stability of PIBs. During the EIR process, Ni‐based metal‐organic framework (Ni‐BPDC) is in situ reconstructed into K‐BPDC by replacing Ni2+ with K+ to make the rest nickel species exist in the form of single atoms in K‐BPDC. By kinetic analysis and theoretical calculations, it is uncovered that the Ni single atoms supported on K‐BPDC efficiently redistribute the local charge of K‐BPDC to accelerate the K+ transport rate, and thermodynamically reduce the redox energy barrier. As a result, the NiSA@K‐BPDC anode exhibits outstanding cycle stability with 88.5% capacity retention during 4000 cycles at 1 A g−1 and an excellent rate capability (114 mAh g−1 at 2 A g−1). This study opens up a new door to the design of organic anodes with single atoms for high‐performance PIBs.