Abstract Aqueous zinc‐ion batteries have drawn increasing attention due to the intrinsic safety, cost‐effectiveness and high energy density. However, parasitic reactions and non‐uniform dendrite growth on the Zn anode side impede their application. Herein, a multifunctional additive, ammonium dihydrogen phosphate (NHP), is introduced to regulate uniform zinc deposition and to suppress side reactions. The results show that the NH4 + tends to be preferably absorbed on the Zn surface to form a “shielding effect” and blocks the direct contact of water with Zn. Moreover, NH4 + and (H2PO4)− jointly maintain pH values of the electrode‐electrolyte interface. Consequently, the NHP additive enables highly reversible Zn plating/stripping behaviors in Zn//Zn and Zn//Cu cells. Furthermore, the electrochemical performances of Zn//MnO2 full cells and Zn//active carbon (AC) capacitors are improved. This work provides an efficient and general strategy for modifying Zn plating/stripping behaviors and suppressing side reactions in mild aqueous electrolyte.

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

Microstructures and mechanical properties evolution of IN939 alloy during electron beam selective melting process

Rechargeable Zn batteries hold great practicability for cost-effective sustainable energy storage but suffer from irreversibility of the Zn anode in aqueous electrolytes due to parasitic H2 evolution, corrosion, and dendrite growth. Herein, we report a non-flammable, dilute, and hydrous organic electrolyte by dissolving low-cost hydrated Zn(ClO4)2·6H2O in trimethyl phosphate (TMP), which homogenizes plating/stripping and enables in situ formation of a Zn3(PO4)2–ZnCl2-rich interphase to stabilize the Zn anode. A dilute 0.5 m Zn(ClO4)2·6H2O/TMP electrolyte featuring a H2O-poor Zn2+-solvation sheath and low water activity enables significantly enhanced Zn reversibility and a wider electrochemical window than the concentrated counterpart. In this formulated electrolyte, the Zn anode exhibits a high efficiency of 99.5% over 500 cycles, long-term cycling for 1200 h (5 mA h cm−2 at 5 mA cm−2) and stable operation at 50 °C. The results would guide the design of hydrous organic electrolytes for practical rechargeable batteries employing metallic electrode materials.

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Non-flammable, dilute, and hydrous organic electrolytes for reversible Zn batteries

Rechargeable aqueous Zn batteries have been widely investigated in recent years due to the merits of high safety and low cost. However inevitable dendrite growth, corrosion and hydrogen evolution of Zn anodes severely compromise the practical lifespan of rechargeable Zn batteries. Despite the encouraging improvements for Zn anodes reported in the literature, the comprehensive understanding of Zn anodes under practical conditions is still often neglected. In this article, we focus on the “less-discussed” but critically important points for rechargeable aqueous Zn batteries, including revisit of the relationship between the coulombic efficiency and lifespan of Zn anodes, the rational control of the pH environment in the vicinity of Zn anodes, the design of appropriate aqueous separators and the relevant estimation of practical energy density for aqueous Zn batteries. It concludes that energy density of 60–80 W h kg−1 for aqueous Zn batteries should be realistic in practice with appropriate cell design. We also propose practical technical recommendations for the rational development of aqueous Zn batteries based on research experience from the community and our group. We hope this article offers readers more practical insights into the future development of aqueous Zn batteries as competitive technology for practical use.

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Towards the practical application of Zn metal anodes for mild aqueous rechargeable Zn batteries

Effective solution treatment can result in improved creep performance of superalloys

Mild aqueous Zn batteries have attracted increasing attention for energy storage due to the advantages of high safety and low cost; however, the rechargeability of Zn anodes is one major issue for practical applications. In this work, an effective approach is proposed to improve the reversibility and stability of Zn anodes using advanced acidic electrolytes. A trace amount of acetic acid (HAc) is employed as a buffering agent to provide a stable pH environment in aqueous Zn electrolytes, and thus suppress passivation from precipitation reactions on Zn electrodes. Meanwhile, tetramethylene sulfone (TMS) is introduced as the critical component to stabilize the Zn anodes in the acidic electrolyte. TMS greatly strengthens the hydrogen-bonding network with reduced H2 O activity and extends the electrochemical window of acidic electrolytes. With the optimal 3 m Zn(OTF)2 in (H2 O-HAc)/TMS acidic electrolyte (pH 1.6), the Zn electrode exhibits a coulombic efficiency of >99.8% and smooth Zn deposition. The Zn-V2 O5 full cell demonstrates ultra-stable cycling over 20 000 cycles with a low decay rate of 0.0009% for each cycle at a negative/postive capacity ratio of 6.5. This work provides an insightful perspective to stabilize Zn electrodes by regulating the pH environment and limiting the H2 O activity simultaneously for long-life Zn anodes.

Advanced Buffering Acidic Aqueous Electrolytes for Ultra-Long Life Aqueous Zinc-Ion Batteries.

A highly sensitive label-free electrochemical aptasensor has been proposed to detect ovarian cancer biomarker cancer antigen 125 (CA125) based on nickel hexacyanoferrate (NiHCF) nanocubes as the in-situ signal probe and polydopamine functionalized graphene ([email protected]) as substrate. NiHCF is a promising candidate in sensing analysis due to its highly reversible redox ability, good stability and easy synthesis. The [email protected] substrate can not only effectively enhance the conductivity and electrochemical activity of the NiHCF, but also covalently interact the aminoated CA125 aptamers with polydopamine by Michael addition reaction. Upon binding of CA125 to the electrode surface by the specifically recognition of aptamer, an insulating layer formed and the electron transfer rate reduced, resulting in the decrease of NiHCF signal. The decreased electrochemical signal can be used to detect CA125 quantitatively. As a result, the designed platform showed excellent sensitivity toward CA125 with a linear response range from 0.10 pg/mL to 1.0 μg/mL and a low detection limit of 0.076 pg/mL. More importantly, this sensing strategy can be extended to detect other biomolecules by simply substituting the aptamer in accordance with the demand. 

A label-free electrochemical aptasensor for the detection of cancer antigen 125 based on nickel hexacyanoferrate nanocubes/polydopamine functionalized graphene

Fenglin Zhang

Papers

Advanced Buffering Acidic Aqueous Electrolytes for Ultra-Long Life Aqueous Zinc-Ion Batteries.

Towards the practical application of Zn metal anodes for mild aqueous rechargeable Zn batteries

Effective solution treatment can result in improved creep performance of superalloys

A label-free electrochemical aptasensor for the detection of cancer antigen 125 based on nickel hexacyanoferrate nanocubes/polydopamine functionalized graphene

Investigation on microstructure evolution of a new disk superalloy under different hot process