Fig. 3: Electrochemical performances of the Zn-CRR/RMOR batteries.
The battery voltage evolution (a) and the corresponding FECO (b) of the Zn-CRR/RMOR batteries with varied RMORs at 4.29 mA cm−2 (with OER as the reference). The initial concentrations of TUDO, ACTO, and Hz in a and b are 7.9, 79, and 92 mM, respectively, and their daily addition amount are 5.2, 26, and 46 mM. c Galvanostatic discharge/charge voltage profiles showing a much lower voltage polarization in Zn-CRR/HzOR batteries than in the Zn-CO2 battery involving OER. d The rate capability measurements showing the voltages of the Zn-CRR/HzOR battery with varied current densities (69 mM Hz). Long-term cycling performance of the Zn-CRR/HzOR battery demonstrating continued high selectivity for CO and voltage stability at 7.14 mA cm−2 (e) and 1.43 mA cm−2 (f). The initial concentration of Hz in e and f is 92 mM, and the daily addition amounts are 23 and 46 mM for e and f, respectively. The FECO was periodically measured for all systems to ensure a proper understanding of the temporal evolution of CRR; the arrows indicate when the Zn anode and anolyte are refreshed, which in the case of HzOR occurs every ten, seven, five days for measurements at 1.43, 4.29, and 7.14 mA cm−2, respectively. For all batteries, each cycle includes 11 min charge and 11 min discharge.
