Decoupled aqueous batteries using pH-decoupling electrolytes

High-Energy and Long-Lived Zn–MnO2 Battery Enabled by a Hydrophobic-Ion-Conducting Membrane

“…Benefiting from the high working voltage and high specific capacity of the two-electron MnO 2 /Mn 2+ reaction in the acidic electrolyte, the HZMB shows a higher discharge plateau (2.05 V) and a larger discharge capacity (0.95 mAh cm –2 ) than those of NZMB (Figure S7), which are consistent with the CV results. Interestingly, the working voltage of the HZMB is even higher (2.05 V) than its theoretical value (1.986 V), which may be attributed to the additional liquid junction potential derived from the concentration difference between the two different electrolytes. , …”

“…Interestingly, the working voltage of the HZMB is even higher (2.05 V) than its theoretical value (1.986 V), which may be attributed to the additional liquid junction potential derived from the concentration difference between the two different electrolytes. 28,37 To evaluate the rate ability of the HZMB, we tested the discharge curves of the HZMB under different current densities ranging from 1 to 20 mA cm −2 . It should be highlighted that the HZMB still displays a discharge plateau of around 1.7 V even at a high discharge current density of 20 mA cm −2 , which is still higher than the theoretical voltage of the NZMB (Figure 3b).…”

“…Herein, to overcome the energy density and lifespan limitations of Zn–MnO 2 batteries, we propose and demonstrate a hybrid Zn–MnO 2 battery (HZMB), in which the acidic MnO 2 cathode and neutral Zn anode are separated by a dual-hydrophobic-induced membrane (polymer/ionic liquid/graphene; PILG). Unlike the water-permeable and commonly used ion-exchange membranes that allow hydrophilic ions, e.g., H + , Li + , Zn 2+ , and SO 4 2– ions to permeate into the membranes, , the PILG membrane repulses the adsorption of any hydrated ions and can only selectively absorb and transport hydrophobic bis­(trifluoromethylsulfonyl)­imide anions (TFSI – ), thereby avoiding the common cross-contamination in hybrid systems and ensuring the optimal reaction conditions for both the cathode and anode. , As a result, the HZMBs exhibit a high working voltage (2.05 V), a high discharge capacity (18 mAh cm –2 ), and long-term cycling capability (2275 h, 2000 cycles), as well as excellent rate performance (20 mA cm –2 ), which will break through the voltage, capacity, and cycling limitations of conventional Zn–MnO 2 batteries.…”

Surface reconstructing hierarchical structures as robust sulfion oxidation catalysts to produce hydrogen with ultralow energy consumption

“…In addition to catalysts, the electrolytes also have an important effect on the reaction voltage and energy consumption. It is worth noting that an acid solution with abundant hydrogen ions is beneficial to HER, 41,42 while SOR occurs more easily in alkaline conditions. 30,43 Besides, an acid and base coupled system possesses a huge negative potential gap that will further promote hydrogen production at an ultralow potential.…”

Highly Reversible Zinc Metal Anode in a Dilute Aqueous Electrolyte Enabled by a pH Buffer Additive

“…Moreover, the interfacial proton concentration (pH) plays a pivotal role in zinc electrodeposition. [18] Under the alkaline environment, zinc electrode would be passivated by the insulating ZnO and Zn(OH) 2 byproducts along with severe Zn dendrite growth, which account for its irreversibility. [4b, 19] In contrast, within the neutral or mild acidic aqueous electrolyte (e.g., 1 M ZnSO 4 ), Zn anode performs much enhanced reversibility with suppressed byproduct formation and less Zn dendrite growth.…”