High cycle stability of Zn anodes boosted by an artificial electronic-ionic mixed conductor coating layer

Aqueous zinc ion batteries (ZIBs) have received widespread attention. Due to serious corrosion of Zn anodes and dendrite growth, further application of ZIBs is hindered. Herein, an artificial mixed electronic-ionic conductive coating layer (Alg-Zn + AB@Zn) consisting of zinc alginate gel (Alg-Zn) and acidified conductive carbon black (AB) is introduced on the surface of Zn. The as-prepared mixed coating not only provides more Zn nucleation sites, but also effectively reduces the nucleation overpotential of Zn. Therefore, the Alg-Zn + AB@Zn symmetrical cell can stably maintain an extremely low voltage hysteresis. Furthermore, Alg-Zn + AB@Zn endows the Zn/AC full cell with excellent cycle stability, especially at high current densities. A capacity retention rate of nearly 100% can be achieved over 10 000 cycles at 10 A g⁻¹, and 16 000 cycles at 20 A g⁻¹, superior to those of the other reported Zn/AC full cells at high current densities, to the best of the authors' knowledge.