Sputtered binder-free Cu3N electrode materials for high-performance quasi-solid-state asymmetric supercapacitors.

Developing high-efficiency electrode materials is of great importance in manufacturing supercapacitor devices with superior electrochemical performance. Herein, we for the first time report a binder-free method for controllable growth of Cu3N electrode materials via magnetron sputtering for supercapacitor applications. Benefiting from their unique polyhedral structure and good electrical conductivity, Cu3N electrodes can achieve an areal capacity of 90.7 mC cm-2 at 1 mA cm-2 and outstanding cycling stability with a capacity retention of 97.4% after 20 000 cycles. In particular, the assembled Cu3N//active carbon quasi-solid-state asymmetric supercapacitor can exhibit a maximum energy density of 13.2 µW h cm-2 and a power density of 4.8 mW cm-2 with an operating voltage of 1.6 V. These remarkable performances demonstrate the great potential of sputtered Cu3N electrode materials for future energy storage applications.

In Situ Alloying Sites Anchored on an Amorphous Aluminum Nitride Matrix for Crystallographic Reorientation of Zinc Deposits.

Secondary aqueous zinc-ion batteries (ZIBs) are considered as one of the promising energy storage devices, but their widespread application is limited by the Zn dendrite issues. In this work, we propose a rational design of surface protective coatings to solve this problem. Specifically, a silver (Ag) nanoparticle embedded amorphous AlN matrix (AlN/Ag) protective layer is developed. The former would alloy in situ with Zn to form AgZn3 alloy sites, which subsequently induce the Zn deposition with preferred (002) facets. The latter can effectively alleviate the structural expansion during repeated Zn plating/stripping. Consequently, the delicately designed AlN/Ag@Zn anode delivers an enhanced stability with a long lifespan of more than 2600 h at 1 mA cm-2 and 1 mAh cm-2. Moreover, the AlN/Ag@Zn||Mn1.4V10O24·nH2O full batteries can be operated for over 8000 cycles under 5 A g-1. Our work not only suggests a promising Zn anode protective coating but also provides a general strategy for the rational design of surface protective layers for metal anodes.

Surface and Interface Engineering of Zn Anodes in Aqueous Rechargeable Zn-Ion Batteries.

Rechargeable zinc-ion batteries (ZIBs) have shown great potential as an alternative to lithium-ion batteries. The ZIBs utilize Zn metal as the anode, which possesses many advantages such as low cost, high safety, eco-friendliness, and high capacity. However, on the other hand, the Zn anode also suffers from many issues, including dendritic growth, corrosion, and passivation. These issues are largely related to the surface and interface properties of the Zn anode. Many efforts have therefore been devoted to the modification of the Zn anode, aiming to eliminate the above-mentioned problems. This review gives a comprehensive summary on the mechanism behind these issues as well as the recent progress on Zn anode modification with focus on the strategies of surface and interface engineering, covering the design and application of both the Zn anode supports and surface protective layers, along with abundant examples. In addition, the promising research directions and perspective on these strategies are also presented.

Electrostatic Shielding Regulation of Magnetron Sputtered Al-Based Alloy Protective Coatings Enables Highly Reversible Zinc Anodes.

The uncontrolled zinc dendrite growth during plating leads to quick battery failure, which hinders the widespread applications of aqueous zinc-ion batteries. The growth of Zn dendrites is often promoted by the "tip effect". In this work, we propose a generate strategy to eliminate the "tip effect" by utilizing the electrostatic shielding effect, which is achieved by coating Zn anodes with magnetron sputtered Al-based alloy protective layers. The Al can form a surface insulating Al2O3 layer and by manipulating the Al content of Zn-Al alloy films, we are able to control the strength of the electrostatic shield, therefore realizing a long lifespan of Zn anodes up to 3000 h at a practical operating condition of 1.0 mA cm-2 and 1.0 mAh cm-2. In addition, the concept can be extended to other Al-based systems such as Ti-Al alloy and achieve enhanced stability of Zn anodes, demonstrating the generality and efficacy of our strategy.

Mn-doped CoSe2 nanosheets as high-efficiency catalysts for the oxygen evolution reaction.

In this work, we introduce for the first time an aqueous solution method followed by a selenization step to prepare Mn-doped CoSe2 nanosheets supported on nickel foam for the oxygen evolution reaction. These findings provide us highly efficient electrocatalysts instead of noble metal catalysts for the oxygen evolution reaction.

Construction of 3D Si@Ti@TiN thin film arrays for aqueous symmetric supercapacitors.

We report the preparation of 3D binder-free Si@Ti@TiN thin film array electrodes for supercapacitors using deep silicon etching and magnetron sputtering for the first time. This work not only offers the 3D array structure of Si@Ti@TiN thin films, but also paves a promising way for the construction of high-energy storage systems.

Accelerating the water splitting kinetics of CoP microcubes anchored on a graphene electrocatalyst by Mn incorporation.

CoP is considered as an efficient electrocatalyst for the hydrogen evolution reaction (HER) in acidic electrolytes but its performance in alkaline solutions is generally poor because of its slow reaction kinetics, which further limits its application in overall water splitting. Herein, we demonstrate a strategy to greatly accelerate its HER and OER kinetics in alkaline solutions through Mn incorporation. Ternary Mn x Co1-x P microcubes with a tunable Mn/Co ratio strongly anchored on rGO were synthesized using Prussian blue analogues as precursors. The synergy between the high activity of Mn x Co1-x P microcubes and the good conductivity of rGO leads to the superior performance of the hybrid toward water splitting in 1 M KOH. The optimized Mn0.6Co0.4P-rGO electrocatalyst shows high activity and stability towards both the HER and OER with low overpotentials of 54 and 250 mV at 10 mA cm-2, respectively. Furthermore, the water electrolyzer using Mn0.6Co0.4P-rGO as both the cathode and anode only requires a cell voltage as low as 1.55 V to reach a current density of 10 mA cm-2, making Mn0.6Co0.4P-rGO a competitive and cost-effective electrocatalyst for water splitting.

Hematite concave nanocubes and their superior catalytic activity for low temperature CO oxidation.

Hematite (α-Fe2O3) concave nanocubes bound by high-index {1344̄} and {123̄8} facets were synthesized and their catalytic activity for CO oxidation were also investigated.