Improved zinc-ion storage performance of the metal-free organic anode by the effect of binder

Zinc-ion batteries (ZIBs) using zinc metal as anode materials suffer from Zn dendrite formation and hydrogen evolution during the stripping/plating process, which will lead to performance degradation and hinder practical application. Herein, the 1,4,5,8-naphthalene diimide (NI) is proposed as a promising dendrite-free organic anode material for ZIBs. Moreover, the effect of different binders on electrochemical performance of NI electrode is investigated. Compared NI electrode with polyvinylidene fluoride (PVDF) binder, the NI electrode with the polytetrafluoroethylene (PTFE) binder shows highly enhanced rate capability (122.2 mA h g(-1) at 5 A g(-1)) and cycling performance (123.3 mA h g(-1) at 3 A g(-1) after 2200 cycles). The improvement cycling stability of NI is attributed to PTFE binder, which effectively maintains electrode structure and inhibits dissolution of organic molecules during the cycling process. In addition, the ion kinetics analyses reveal that the superior rate capability is provided by the capacitive charge storage. And the carbonyl group of NI is active center of electrochemistry, which is revealed by in-situ attenuated total reflection-Fourier transform infrared (ATR-FTIR) and ex-situ Raman. Besides, the aqueous Zn-ion full cell based on metal-free NI anode and Prussian blue analogues (PBAs) cathode exhibits excellent rate capability (113.9 mA h g(-1) at 10.0 A g(-1)), high operation voltage of similar to 1.2 V (at 1.0 A g(-1)) and energy density of 50.2 Wh kg(total)(-)(1). This work may provide a new design inspiration to develop organic dendrite-free zinc anodes for high-performance aqueous ZIBs batteries.

Automated summary

The study introduces an organic dendrite-free anode material, NI, and demonstrates that using PTFE binder significantly improves the rate performance and cycling stability of the NI electrode.