A nano-copper particle-modified zinc anode as a protective coating enables dendrite-free aqueous zinc-ion batteries.

Aqueous zinc-ion batteries (AZIBs) have become one of the hotspots in large-scale energy storage due to their advantages of high safety, low cost, and environmental friendliness. However, the metallic Zn anode is prone to dendritic growth and electrochemical corrosion on the surface during cycling, posing a serious challenge to the cycling life of AZIBs. Herein, a simple, low-cost and suitable for mass production method is reported to construct an anti-corrosive nano-copper particle protective coating on the surface of a metallic zinc (Cu-Zn) anode. The prepared nano-copper particles are evenly distributed on the surface of Zn, providing a uniform electric field distribution and successfully suppressing electrochemical corrosion on the surface. Importantly, it is confirmed microscopically that the Cu-Zn anode maintains homogeneous stripping and plating processes, effectively alleviating dendrite formation. Additionally, the resulting Cu-Zn anode exhibits a lower overpotential, which offers a lower interfacial transfer resistance of the battery. The symmetric battery test results show that the unmodified bare Zn anode fails after 58 h at 1 mA cm-2 and 0.5 mA h cm-2, while the Cu-Zn anode can remain stable for more than 3200 h. Furthermore, the assembled Cu-Zn||α-MnO2 battery delivers a capacity of 173.2 mA h g-1 after 2500 cycles at a high current density of 2000 mA g-1, and the capacity retention rate is 90.6%. The results indicate the great potential application of the nano-copper particle-modified zinc anode, which has provided an appealing strategy for improving the stability of AZIBs to promote the industrial development of the energy storage field.

Aqueous Organic Batteries Using the Proton as a Charge Carrier.

Benefiting from the merits of low cost, nonflammability, and high operational safety, aqueous rechargeable batteries have emerged as promising candidates for large-scale energy-storage applications. Among various metal-ion/non-metallic charge carriers, the proton (H+ ) as a charge carrier possesses numerous unique properties such as fast proton diffusion dynamics, a low molar mass, and a small hydrated ion radius, which endow aqueous proton batteries (APBs) with a salient rate capability, a long-term life span, and an excellent low-temperature electrochemical performance. In addition, redox-active organic molecules, with the advantages of structural diversity, rich proton-storage sites, and abundant resources, are considered attractive electrode materials for APBs. However, the charge-storage and transport mechanisms of organic electrodes in APBs are still in their infancy. Therefore, finding suitable electrode materials and uncovering the H+ -storage mechanisms are significant for the application of organic materials in APBs. Herein, the latest research progress on organic materials, such as small molecules and polymers for APBs, is reviewed. Furthermore, a comprehensive summary and evaluation of APBs employing organic electrodes as anode and/or cathode is provided, especially regarding their low-temperature and high-power performances, along with systematic discussions for guiding the rational design and the construction of APBs based on organic electrodes.

A Novel Aqueous Asymmetric Supercapacitor based on Pyrene-4,5,9,10-Tetraone Functionalized Graphene as the Cathode and Annealed Ti3 C2 Tx MXene as the Anode.

Asymmetric supercapacitors (ASCs), employing two dissimilar electrode materials with a large redox peak position difference as cathode and anode, have been designed to further broaden the voltage window and improve the energy density of supercapacitors. Organic molecule based electrodes can be constructed by combining redox-active organic molecules with conductive carbon-based materials such as graphene. Herein, pyrene-4,5,9,10-tetraone (PYT), a redox-active molecule with four carbonyl groups, exhibits a four-electron transfer process and can potentially deliver a high capacity. PYT is noncovalently combined with two different kinds of graphene (Graphenea [GN] and LayerOne [LO]) at different mass ratios. The PYT-functionalized GN electrode (PYT/GN 4-5) possesses a high capacity of 711 F g-1 at 1 A g-1 in 1 M H2 SO4 . To match with the PYT/GN 4-5 cathode, an annealed-Ti3 C2 Tx (A-Ti3 C2 Tx ) MXene anode with a pseudocapacitive character is prepared by pyrolysis of pure Ti3 C2 Tx . The assembled PYT/GN 4-5//A-Ti3 C2 Tx ASC delivers an outstanding energy density of 18.4 Wh kg-1 at a power density of 700 W kg-1 . The PYT-functionalized graphene holds great potential for high-performance energy storage devices.

Uniform Bi-Bi2O3 nanoparticles/reduced graphene oxide composites for high-performance aqueous alkaline batteries.

Aqueous alkaline batteries (AABs) with the merits of both high energy density and power density have emerged as one of the most promising candidates for the new generation of energy storage devices, while their practical applications are still limited by the lack of high-performance electrode materials, especially for the anode materials. Herein, metallic bismuth-bismuth oxide nanoparticles (Bi-Bi2O3), with numerous heterogeneous interfaces, are successfully anchored and uniformly distributed on reduced graphene oxide (rGO) sheets. When Bi-Bi2O3/rGO-20 electrode is used as the anode material for an AAB, it shows a high specific capacity of 288.0 mA h g-1 (1036.9 F g-1) at 1 A g-1 and good rate capability (74.7% of capacity retention ratio at 20 A g-1). Additionally, in order to match well with a Bi-Bi2O3/rGO-20 anode, CoVSx thin sheets decorated with Ni-Co layered double hydroxide sheets (NiCo-LDH) were successfully constructed via a facile multistep hydrothermal method and a subsequent electrodeposition process. The resulting cathode exhibits a high specific capacity of 306.0 mA h g-1 (2448 F g-1) at 1 A g-1. The assembled CoVSx@NiCo-LDH//Bi-Bi2O3/rGO-20 AAB delivers an outstanding energy density of 106.1 Wh kg-1 at a power density of 789.6 W kg-1. Besides, the as-synthesized Bi-based electrode is also used in aqueous Zn alkaline batteries to further extend its application and the assembled Bi-Bi2O3/rGO-20//Zn batteries possess an ultralong flat discharge plateau and exhibit a specific capacity of 250.6 mA h g-1 at 1 A g-1. The results demonstrate that the as-assembled AAB has huge potential for practical applications and provides an inspiration for the next-generation energy storage devices.