Uniform Zn Deposition Achieved by Conductive Carbon Additive for Zn Anode in Zinc-Ion Hybrid Supercapacitors

The nonuniform zinc nucleation process on the surface of zinc metal anodes is known to result in irreversible dendrite growth, which brings the risk of short circuit for the zinc-ion hybrid supercapacitor (ZIHS). Herein, a conductive carbon-zinc composite anode with dense active sites is reported to achieve controllable dendrite growth. This unique modified anode in the ZIHS enables extremely low polarization (47 mV) in the symmetric battery test and delivers excellent application performance (capacity retention of 97.7% for 10 000 cycles). In addition, the changes in crystallographic orientation and morphological characteristics of the zinc electrode during deposition are observed by ex situ analysis. The improved zinc nucleation pattern of the modified anode verifies that the carbon additive can significantly facilitate isotropy in Zn deposition. Such a successful application of this economic and expandable modification strategy shows that carbon additives have significant potential in improving the stability of the anode.