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).