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

The 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. High-loading Ni single atoms (approximate to 6 wt%) modified potassium 1,1 '-biphenyl-4,4 '-dicarboxylate (NiSA@K-BPDC) is synthesized by electrochemical-induced reconstruction strategy as organic anodes of PIBs, of which Ni single atoms redistribute the local charge of K-BPDC to enhance the K+ transport rate and reduce the energy barrier of K-BPDC redox reaction, contributing to a dramatic improvement in capacity, kinetics, and cycling performance. image