Stable and Dendrite-Free Zn Anode Enabled by a PEDOT:PSS Layer for High-Performance Zn-Ion Capacitors

Aqueous zinc-ion capacitors (ZICs) are expected to become a new generation of energy storage systems because of their unique advantages. However, the dendritic problem of the Zn anode is still a bottleneck for their large-scale applications. Herein, we introduce a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer on a Zn anode to tackle the dendrite issue. Benefiting from good adhesion and film-forming characteristics, PEDOT:PSS is evenly coated on a zinc anode surface by a simple coating strategy to form a dense artificial film. The well-ordered PEDOT:PSS layer can effectively regulate the deposition direction of zinc ions and effectively prevent water from the zinc surface, resulting in uniform Zn plating/stripping without dendrite growth. A symmetrical cell assembled with PEDOT:PSS@Zn exhibits dendrite-free Zn plating/stripping behavior with stable cycling over 2670 h at a current density of 0.5 mA cm–2 and can also operate correctly at 10 mA cm–2 for up to 420 h. In addition, this ultrastable anode is equipped with an AC cathode to enable a stable full capacitor with long cycle stability (10,000 cycles).