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Constructing the magnesium alloy with fine grains, low density of dislocations, and weak crystal orientation is of crucial importance to enhance its comprehensive performance as the anode for Mg-air battery. However, this unique microstructure can hardly be achieved with conventional plastic deformation such as rolling or extrusion. Herein, we tailor the microstructure of Mg-Al-Sn-RE alloy by using the friction stir processing, which obviously refines the grains without increasing dislocation density or strengthening crystal orientation. The Mg-air battery with the processed Mg-Al-Sn-RE alloy as the anode exhibits higher discharge voltages and capacities than that employing the untreated anode. Furthermore, the impact of friction stir processing on the electrochemical discharge behaviour of Mg-Al-Sn-RE anode and the corresponding mechanism are also analysed according to microstructure characterization and electrochemical response.

Metal–organic frameworks have emerged as promising electrode materials for metal-ion batteries due to their superior structural customizability. However, they face challenges such as poor reversibility and easy degradation during electrochemical redox processes. Here, we report the synthesis of π-d conjugated coordination polymers through NH3-vapor-assisted self-polymerization of NiCl2·6H2O with 1,2,4,5-benzenetetramine tetrahydrochloride (namely, Ni-BTA). The synthesized Ni-BTA exhibits an open lattice structure that enhances the capacity for metal-ion diffusion, ensuring prolonged electrochemical cycling stability. Moreover, electrochemical characterizations reveal that Ni-BTA functions as a bifunctional material, serving as both cathode and anode materials for lithium-ion batteries (LIBs). After 1,000 cycles at 1.0 A g−1, the cathode and anode show high discharge capacities of 199.7 and 338.4 mAh g−1, respectively. Additionally, symmetrical all-organic batteries constructed with Ni-BTA exhibit a high specific capacity of 30.6 mAh g–1 and an ultrastable coulombic efficiency of approximately ≈100% after 6,000 cycles at 1.0 A g−1. Furthermore, Ni-BTA exhibits versatility as a robust cathode for aluminum ion batteries (AIBs), delivering a discharge capacity of 18.7 mAh g−1 after 10,000 cycles at 1.0 A g−1. These findings highlight the potential of Ni-BTA as a versatile and durable electrode materials for both LIBs and AIBs.

Highlights Three-dimensional (3D) core‐shell heterostructured NixSy@MnOxHy nanorods grown on nickel foam (NixSy@MnOxHy/NF) were successfully fabricated via a simple hydrothermal reaction and a subsequent electrodeposition process. The fabricated NixSy@MnOxHy/NF shows outstanding bifunctional activity and stability for hydrogen evolution reaction and oxygen evolution reaction, as well as overall‐water‐splitting performance. The main origins are the interface engineering of NixSy@MnOxHy, the shell‐protection characteristic of MnOxHy, and the 3D open nanorod structure, which remarkably endow the electrocatalyst with high activity and stability. Abstract Exploring highly active and stable transition metal-based bifunctional electrocatalysts has recently attracted extensive research interests for achieving high inherent activity, abundant exposed active sites, rapid mass transfer, and strong structure stability for overall water splitting. Herein, an interface engineering coupled with shell-protection strategy was applied to construct three-dimensional (3D) core‐shell NixSy@MnOxHy heterostructure nanorods grown on nickel foam (NixSy@MnOxHy/NF) as a bifunctional electrocatalyst. NixSy@MnOxHy/NF was synthesized via a facile hydrothermal reaction followed by an electrodeposition process. The X-ray absorption fine structure spectra reveal that abundant Mn‐S bonds connect the heterostructure interfaces of NixSy@MnOxHy, leading to a strong electronic interaction, which improves the intrinsic activities of hydrogen evolution reaction and oxygen evolution reaction (OER). Besides, as an efficient protective shell, the MnOxHy dramatically inhibits the electrochemical corrosion of the electrocatalyst at high current densities, which remarkably enhances the stability at high potentials. Furthermore, the 3D nanorod structure not only exposes enriched active sites, but also accelerates the electrolyte diffusion and bubble desorption. Therefore, NixSy@MnOxHy/NF exhibits exceptional bifunctional activity and stability for overall water splitting, with low overpotentials of 326 and 356 mV for OER at 100 and 500 mA cm–2, respectively, along with high stability of 150 h at 100 mA cm–2. Furthermore, for overall water splitting, it presents a low cell voltage of 1.529 V at 10 mA cm–2, accompanied by excellent stability at 100 mA cm–2 for 100 h. This work sheds a light on exploring highly active and stable bifunctional electrocatalysts by the interface engineering coupled with shell-protection strategy.

Abstract Compared with commercial lithium batteries with liquid electrolytes, all‐solid‐state lithium batteries (ASSLBs) possess the advantages of higher safety, better electrochemical stability, higher energy density, and longer cycle life; therefore, ASSLBs have been identified as promising candidates for next‐generation safe and stable high‐energy‐storage devices. The design and fabrication of solid‐state electrolytes (SSEs) are vital for the future commercialization of ASSLBs. Among various SSEs, solid polymer composite electrolytes (SPCEs) consisting of inorganic nanofillers and polymer matrix have shown great application prospects in the practice of ASSLBs. The incorporation of inorganic nanofillers into the polymer matrix has been considered as a crucial method to achieve high ionic conductivity for SPCE. In this review, the mechanisms of Li+ transport variation caused by incorporating inorganic nanofillers into the polymer matrix are discussed in detail. On the basis of the recent progress, the respective contributions of polymer chains, passive ceramic nanofillers, and active ceramic nanofillers in affecting the Li+ transport process of SPCE are reviewed systematically. The inherent relationship between the morphological characteristics of inorganic nanofillers and the ionic conductivity of the resultant SPCE is discussed. Finally, the challenges and future perspectives for developing high‐performance SPCE are put forward. This review aims to provide possible strategies for the further improvement of ionic conductivity in inorganic nanoscale filler‐reinforced SPCE and highlight their inspiration for future research directions.

Abstract As bifunctional oxygen evolution/reduction electrocatalysts, transition-metal-based single-atom-doped nitrogen–carbon (NC) matrices are promising successors of the corresponding noble-metal-based catalysts, offering the advantages of ultrahigh atom utilization efficiency and surface active energy. However, the fabrication of such matrices (e.g., well-dispersed single-atom-doped M-N4/NCs) often requires numerous steps and tedious processes. Herein, ultrasonic plasma engineering allows direct carbonization in a precursor solution containing metal phthalocyanine and aniline. When combining with the dispersion effect of ultrasonic waves, we successfully fabricated uniform single-atom M-N4 (M = Fe, Co) carbon catalysts with a production rate as high as 10 mg min−1. The Co-N4/NC presented a bifunctional potential drop of ΔE = 0.79 V, outperforming the benchmark Pt/C-Ru/C catalyst (ΔE = 0.88 V) at the same catalyst loading. Theoretical calculations revealed that Co-N4 was the major active site with superior O2 adsorption–desorption mechanisms. In a practical Zn–air battery test, the air electrode coated with Co-N4/NC exhibited a specific capacity (762.8 mAh g−1) and power density (101.62 mW cm−2), exceeding those of Pt/C-Ru/C (700.8 mAh g−1 and 89.16 mW cm−2, respectively) at the same catalyst loading. Moreover, for Co-N4/NC, the potential difference increased from 1.16 to 1.47 V after 100 charge–discharge cycles. The proposed innovative and scalable strategy was concluded to be well suited for the fabrication of single-atom-doped carbons as promising bifunctional oxygen evolution/reduction electrocatalysts for metal–air batteries.