Suppressing Hydrogen Evolution and Dendrite Formation on a Zn Anode by Coating In2O3 with Tailored Affinity to H* and Zn*

To suppress the hydrogen evolution reaction (HER) and dendrite formation on the Zn anode in aqueous Zn-ion batteries, a submicrometer In 2 O 3 coating on the Zn anode (referred to as Zn@In 2 O 3 ) was constructed via magnetron sputtering. Density functional theory (DFT) and experimental data show that the In 2 O 3 coating suppresses the HER because of its weaker interactions with H* compared with Zn, inhibiting the Volmer step. At the same time, the In 2 O 3 coating exhibits a moderate affinity for Zn*, higher than that on Zn but lower than that at the In 2 O 3 –Zn interface, thus facilitating the desolvation of the hydrated Zn 2+ ions while promoting its deposition on the Zn substrate beneath the In 2 O 3 coating. The resultant suppression of side reactions and dendrite growth significantly enhance the reversible plating/stripping of Zn. The optimized Zn@In 2 O 3 stably cycles over 6400 h with a low voltage hysteresis of 9.5 mV at 1 mA cm –2 and 1 mAh cm –2 in symmetric cells. The average Coulombic efficiency of Zn plating/stripping is increased from 95.8 to 99.6% owing to the In 2 O 3 coating. Moreover, when coupled with the Mn 0.15 V 2 O 5 ·nH 2 O cathode, the Zn@In 2 O 3 battery maintains a capacity retention of 78.6% after 2000 cycles at 5 A g –1 . This facile and economical modification of Zn anodes provides an idea for realizing the practical application of AZIBs.