Aqueous Zn-based batteries deliver thousands of cycles at high rates but poor recyclability at low rates. Herein, we reveal that such illogical phenomenon is attributed to the reconstructed electrode/electrolyte interface...
Alkaline Zn–MnO2 batteries feature
high security,
low cost, and environmental friendliness while suffering from severe
electrochemical irreversibility for both the Zn anode and MnO2 cathode. Although neutral electrolytes are supposed to improve
the reversibility of the Zn anode, the MnO2 cathode indeed
experiences a capacity degradation caused by the Jahn–Teller
effect of the Mn3+ ion, thus shortening the lifespan of
the neutral Zn–MnO2 batteries. Theoretically, the
MnO2 cathode undergoes a highly reversible two-electron
redox reaction of the MnO2/Mn2+ couple in strongly
acidic electrolytes. However, acidic electrolytes would inevitably
accelerate the corrosion of the Zn anode, making long-lived acidic
Zn–MnO2 batteries impossible. Herein, to overcome
the challenges faced by Zn–MnO2 batteries, we propose
a hybrid Zn–MnO2 battery (HZMB) by coupling the
neutral Zn anode with the acidic MnO2 cathode, wherein
the neutral anode and acidic cathode are separated by a proton-shuttle-shielding
and hydrophobic-ion-conducting membrane. Benefiting from the optimized
reaction conditions for both the MnO2 cathode and Zn anode
as well as the well-designed membrane, the HZMB exhibits a high working
voltage of 2.05 V and a long lifespan of 2275 h (2000 cycles), breaking
through the limitations of Zn–MnO2 batteries in
terms of voltage and cycle life.
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