Long-Life Zn Anode Enabled with Complexing Ability of a Benign Electrolyte Additive.

The development of aqueous zinc ion batteries (AZIBs) is hindered by several problems, including Zn dendrite/corrosion, side reactions, and hydrogen evolution reaction (HER). Herein, trisodium citrate (NaCit) additive is introduced into the ZnSO4 electrolyte to guide the preferred Zn(002) crystal plane growth, while the Cit- is preferentially adsorbed on the active sites to suppress the HER and Zn corrosion, thus achieving uniform Zn deposition without dendrites. The stable cycle life can reach 2000 h at 0.25 mA cm-2/0.05 mAh cm-2. The density functional theory simulations further indicate that the parallely placed Cit- has the lowest adsorption energy (-6.617 eV); it can form a weak interaction with Zn metal to promote the growth of (002) crystal planes. Furthermore, the assembled Zn//polyaniline full cell and pouch cell both exhibit good rate performance and long cycling stability. The complexation and dissolubilization effects of the NaCit additive provide a means for designing high-performance AZIBs.

Prussian blue analogue assisted formation of iron doped CoNiSe2 nanosheet arrays for efficient oxygen evolution reaction.

Electrochemical water splitting is a promising approach to produce hydrogen gas, but sluggish four-electron transfer of the oxygen evolution reaction (OER) severely limits the overall energy conversion efficiency of water splitting. Herein, as an excellent OER electrocatalyst, a technique of synthesizing Fe doped CoNiSe2 nanosheet (Fe-CoNiSe2) whole series using CoFe prussian blue analog produced by Co-ZIF-L reaction as a template is proposed here. The introduction of iron ions promotes the redistribution of the cobalt-nickel charge density, which enhances the OER kinetics. In view of the abovementioned points, Fe-CoNiSe2/NF has excellent activity, electrocatalytic properties and excellent stability in alkaline media, which only demands a lower overpotential of 244 mV and 271 mV to deliver a current density of 10 mA cm-2 and 50 mA cm-2, respectively. The material also exhibits excellent stability for at least 24 h during the OER process. This work may provide some new insights into the assembly of advanced and highly-active materials for a variety of other energy conversion applications.

Synthesis of Porous δ-MnO2 Submicron Tubes as Highly Efficient Electrocatalyst for Rechargeable Li-O2 Batteries.

Lithium-oxygen (Li-O2 ) batteries are receiving intense interest because of their high energy density. A new tubular δ-MnO2 material prepared by a simple hydrothermal synthesis is an efficient electrocatalyst for Li-O2 batteries. The synthesized δ-MnO2 exhibits a unique tubular structure, in which the porous walls are composed of highly dispersed ultrathin δ-MnO2 nanosheets. Such a unique structure and its intrinsic catalytic activity provide the right electrocatalyst characteristics for high-performance Li-O2 batteries. As a consequence, suppressed overpotentials-especially the oxygen evolution reaction overpotential-superior rate capability, and desirable cycle life are achieved with these submicron δ-MnO2 tubes as the electrocatalyst. Remarkably, the discharge product Li2 O2 of the Li-O2 battery exhibits a uniform nanosheet-like morphology, which indicates the critical role of the δ-MnO2 in the electrochemical process, and a mechanism is proposed to analyze the catalysis of δ-MnO2 .

Hierarchically porous and nitrogen, sulfur-codoped graphene-like microspheres as a high capacity anode for lithium ion batteries.

Novel hierarchically porous and nitrogen, sulfur-codoped graphene-like microspheres (3D NS-GSs) are synthesized using Ni microspheres as the template and using poly(vinylpyrrolidone) and (NH4)2S2O8 as the carbon and nitrogen precursor, respectively. As an anode material in lithium ion batteries, the 3D NS-GS electrode displays a superior capacity with excellent cycling stability.