• Energy Research

The flexible utilization of renewables for power-to-fuel and/or power-to-power is enabled by the decoupled amphoteric water electrolysis and Mn–Zn battery.

The flexible utilization of renewables for power-to-fuel and/or power-to-power is enabled by the decoupled amphoteric water electrolysis and Mn–Zn battery.

Trace-amount additive (10 mM, 0.1 wt%), ammonium succinate, was introduced to endow electrolyte with excellent pH buffering ability, resulting in high CE (99.91% and 99%) at low current density (1 mA cm−2 and 0.5 mA cm−2) and high cycle stability.

Trace-amount additive (10 mM, 0.1 wt%), ammonium succinate, was introduced to endow electrolyte with excellent pH buffering ability, resulting in high CE (99.91% and 99%) at low current density (1 mA cm−2 and 0.5 mA cm−2) and high cycle stability.

A carbonate-based electrolyte is well-designedviaa multifunctional lithium difluorobis(oxalato) phosphate (LiDFBOP) additive, endowing 4.5 V sodium metal batteries with high energy density, excellent cycling stability and a wide temperature range.

A carbonate-based electrolyte is well-designedviaa multifunctional lithium difluorobis(oxalato) phosphate (LiDFBOP) additive, endowing 4.5 V sodium metal batteries with high energy density, excellent cycling stability and a wide temperature range.

Summary: Water electrolysis powered by renewables provides a green approach to hydrogen production to support the “hydrogen economy.” However, the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are tightly coupled in both time and space in traditional water electrolysis, which brings inherent operational challenges, such as the mixture of H2/O2 and the limited HER rate caused by the sluggish kinetics of OER. Against this background, decoupling H2 and O2 production in water electrolysis by using the auxiliary redox mediator was first proposed in 2013, in which O2 and H2 are produced at different times, rates, and/or locations. The decoupling strategy offers not only a new way to facilitate renewables to H2, but it can also be applied in other chemical or electrochemical processes. This review describes recent efforts to develop high-performance redox mediators, optimized strategies in decoupled water electrolysis, the design of electrolyzer configuration, the challenges faced, and the prospective directions.

Summary: Water electrolysis powered by renewables provides a green approach to hydrogen production to support the “hydrogen economy.” However, the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are tightly coupled in both time and space in traditional water electrolysis, which brings inherent operational challenges, such as the mixture of H2/O2 and the limited HER rate caused by the sluggish kinetics of OER. Against this background, decoupling H2 and O2 production in water electrolysis by using the auxiliary redox mediator was first proposed in 2013, in which O2 and H2 are produced at different times, rates, and/or locations. The decoupling strategy offers not only a new way to facilitate renewables to H2, but it can also be applied in other chemical or electrochemical processes. This review describes recent efforts to develop high-performance redox mediators, optimized strategies in decoupled water electrolysis, the design of electrolyzer configuration, the challenges faced, and the prospective directions.

A zinc anode with high Zn(002)-preferential orientation can be achieved using a universal proton additive, which has been shown to effectively suppress dendrite formation in aqueous zinc batteries.