Solar charging of a Zn-air battery

A brief review on solar charging of Zn–air batteries

“…Charging then of the Zn-air battery means reproduction of Zn at the zinc electrode and oxygen evolution at the gas-diffusion electrode. The minimum electric bias necessary to achieve these reactions is 1.65 V. In reality, it is higher than 2 V 15,16 due to losses and mainly due to the overpotential necessary to achieve the energetically difficult 4-electron oxygen evolution reaction (OER).…”

“…Various approaches have been adopted in order to decrease this large electric bias. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] They will be reviewed here below.…”

“…Spatial separation of the charging from the discharging process opens the possibility for solar charging of the Zn-air battery. [16][17][18][19][20]33 Fig. 3 shows a set up for such a case.…”

“…Charging of the Zn–air battery corresponds to the reversal of reactions (1)–(3): 4 Zn electrode Zn(OH) 4 2− + 2e − → Zn + 4OH − (Zn 2+ → Zn)Counter electrode 4OH − → O 2 + 4e − + 2H 2 OCharging then of the Zn–air battery means reproduction of Zn at the zinc electrode and oxygen evolution at the gas-diffusion electrode. The minimum electric bias necessary to achieve these reactions is 1.65 V. In reality, it is higher than 2 V 15,16 due to losses and mainly due to the overpotential necessary to achieve the energetically difficult 4-electron oxygen evolution reaction (OER). Various approaches have been adopted in order to decrease this large electric bias.…”

Research progress on the construction of synergistic electrocatalytic ORR/OER self-supporting cathodes for zinc–air batteries

“…3,4 Among them, Zn-air batteries (ZABs) show relatively higher power density (z1084 W h kg −1 ), stable discharge voltage, and produce water as a pollution-free product, which is consistent with sustainable development and environmental friendliness. [5][6][7] The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are the discharging and charging reactions of the air-cathode, respectively. [8][9][10] However, these two reactions involve multiple electron transfer processes with slow reaction kinetics, and thus it is necessary to develop efficient catalysts to accelerate their kinetic processes.…”