Modified polydopamine derivatives as high-performance organic anodes for potassium-ion batteries

Polydopamine (PDA) as a carbon source and a versatile coating material has been widely studied in rechargeable battery electrodes. However, it is rare to directly utilize PDA as an organic anode for ion storage, especially in potassium-ion batteries (PIBs). In this work, modified PDA (MPDA-350) with a porous structure is synthesized by collective methods of template-assisted and low-temperature pyrolysis, which endows PDA with large ion diffusion tunnels and increased active sites for K+ ion storage. Moreover, contrast experiments demonstrate that the annealing process with an appropriate temperature can increase the content and activity of electroactive groups in MPDA-350. The prepared MPDA-350 is first applied to PIBs that deliver high reversible capacity (384.9 mA h g(-1) at 100 mA g(-1)) and very stable cyclability (99.94% capacity retention after 500 cycles). This work provides a new insight for the expansion of high-performance organic anodes for PIBs.