Aqueous Zn metal batteries suffer from rapid cycling deterioration due to the severe water corrosion and dendrite growth o n Z n a n o d e s . H e r e i n , a h i g h l y a n t i w a t e r Z n xdiethylenetriaminepenta(methylene-phosphonic acid) interface layer with good zinc affinity and special nanoscaled 3D granular structure is designed on Zn metal to address these problems. Experimental results combined with theoretical analysis and COMSOL simulations reveal that the hydrophobic groups in such Zn-based organic complex are the decisive factor in preventing H 2 O from damaging Zn anode surface. The massive Zn 2+ attractive sites formed by interaction of methylene-phosphonic acid groups and Zn cause ion channel for fast zinc-ion adsorption and migration. And the developed nano granular architecture on the surface induces redistributed Zn 2+ ion flux to realize homogenization with smooth and compact surface deposition. Under the synergism, such modified anodes exhibit long cycling lifespan over 1300 h with a relatively low polarization voltage at 5 mA cm −2 . Also, the assembled full cells (including Zn//V 2 O 5 and Zn//MnO 2 cell) based on this anode are also demonstrated. The work provides a simple, low cost, and efficient pathway by combining the two concepts of structural design and constructing protective layers on the surface to prepare high-performance Zn anodes toward prospering aqueous zinc−metal batteries.
Unstable electrode/electrolyte interface with inhomogeneous Zn deposition and side reactions plagues the practical application of aqueous Zn-ion batteries. Herein, L-carnitine (L-CN) is proposed to stabilize both electrodes and extend the...
The practical application of aqueous zinc batteries (AZBs) is significantly limited by the poor reversibility of the zinc anodes, including rampant dendrite growth and severe interfacial side-reactions. Herein, trace hexamethylenetetramine (HMTA) additive with a lone-pair-electron containing heterocycle is introduced for Zn metal anode protection. Specifically, the trace added HMTA can change the solvated structure by strong interaction with zinc ions, and preferentially absorb on the anode surface to in situ establish an unique anode-molecule interface. Such an interface not only shows strong affinity to promote the dynamic transmission and deposition of Zn 2+ ions but also displays a role in suppressing parasitic reactions. Consequently, a zinc anode in an electrolyte with trace HMTA achieves a high Coulombic efficiency of 99.75%, and delivers a remarkable lifespan over 4000 h at 5 mA cm −2 and 1 mAh cm −2 in a Zn//Zn symmetric cell. Even under a deep plating/stripping condition (5 mA cm −2 and 5 mAh cm −2 ), it can still run almost for 600 h. Additionally, the Zn//V 2 O 5 full cell with HMTA retains a high capacity retention of 61.7% after 4000 cycles at 5 A g −1 . Such an innovative strategy is expected to be of immediate benefit to design low-cost AZBs with ultra-long lifespan.
As promising candidates for aqueous metal batteries, aqueous zinc‐ion batteries (ZIBs) have attracted more attention due to their superior safety, low cost, and environmentally benign characteristics. Solvent water plays a double‐edged sword role that cannot be ignored in the electrochemical performance and long cycling stability of the batteries. The hydrated zinc ions of the solvated structure can boost the diffusion kinetics of zinc ions, whereas the released active water molecules during desolvation can lead to notorious hydrogen evolution reactions, dendrites growth, and surface passivation at the unstable interface between the electrolyte and the anode. Unlike previous reports that summarize recent research progress, this review focuses on the double‐edged sword role of water molecules in the anode during electrochemical processes in ZIBs. The influencing mechanism of water molecules on the stability of zinc anode during the energy storage process is systematically discussed, including the basic theory, water regulation strategies, and recent reports. The two‐faced identity of the water molecules in aqueous electrolyte is profoundly revealed herein, and some revelatory insights and possible strategies are provided for the future design on stable and durable zinc anodes of high‐performance ZIBs.
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