NiFeS nanosheet array on Ni foam (NiFeS/NF) behaves as a superb bifunctional electrocatalyst for overall seawater splitting, attaining a commercially demanded current density of 500 mA cm ⁻² at a low cell voltage of 1.85 V with robust stability.

In this review, research progress on layered oxide cathodes for SIBs in recent years is summarized, with emphasis on the problems of poor cycle life caused by irreversible phase transition, Jahn–Teller effect and interface deterioration, and several strategies are proposed to alleviate these issues.

NH₃ is an essential feedstock for fertilizer synthesis. Industry-scale NH₃ synthesis mostly relies on the Haber-Bosch method, however, which suffers from massive CO₂ emission and high energy consumption. Electrocatalytic NO₃⁻ reduction is an attractive substitute to the Haber-Bosch method for synthesizing NH₃ under mild conditions. As this reaction will produce a variety of products, it highly desires efficient and selective electrocatalyst for NH₃ generation. Here, we report in situ grown Fe₃O₄ particle on stainless steel (Fe₃O₄/SS) as a high-efficiency electrocatalyst for NO₃⁻ reduction to NH₃. In 0.1 M NaOH with 0.1 M NaNO₃, such Fe₃O₄/SS reaches a remarkable Faradaic efficiency of 91.5% and a high NH₃ yield of 10,145 µg·h⁻¹·cm⁻² at −0.5 V vs. reversible hydrogen electrode (RHE). Furthermore, it owns robust structural and electrochemical stability. This work provides useful guidelines to expand the scope of metallic oxide electrocatalysts for NH₃ synthesis. The catalytic mechanism is uncovered and discussed further by theoretical calculations.

Industrial-scale ammonia (NH₃) production mainly relies on the energy-intensive and environmentally unfriendly Haber-Bosch process. Such issue can be avoided by electrocatalytic N₂ reduction which however suffers from limited current efficiency and NH₃ yield. Herein, we demonstrate ambient NH₃ production via electrochemical nitrite (NO₂⁻) reduction catalyzed by a CoP nanoarray on titanium mesh (CoP NA/TM). When tested in 0.1 M PBS (pH = 7) containing 500 ppm NO₂⁻, such CoP NA/TM is capable of affording a large NH₃ yield of 2,260.7 ± 51.5 µg·h⁻¹·cm⁻² and a high Faradaic efficiency of 90.0 ± 2.3% at −0.2 V vs. a reversible hydrogen electrode. Density functional theory calculations reveal that the potential-determining step for NO₂⁻ reduction over CoP (112) is *NO₂ → *NO₂H.

Limited lithium resources have promoted the exploration of new battery technologies. Among them, potassium‐ion batteries are considered as promising alternatives. At present, commercial graphite and other carbon‐based materials have shown good prospects as anodes for potassium‐ion batteries. However, the volume expansion and structural collapse caused by periodic K⁺ insertion/extraction have severely restricted further development and application of potassium‐ion batteries. A hollow biomass carbon ball (NOP‐PB) ternarily doped with N, O, and P was synthesized and used as the negative electrode of a potassium‐ion battery. X‐ray photoelectron spectroscopy, Fourier‐transform infrared spectroscopy, and transmission electron microscopy confirmed that the hollow biomass carbon spheres were successfully doped with N, O, and P. Further analysis proved that N, O, and P ternary doping expands the interlayer distance of the graphite surface and introduces more defect sites. DFT calculations simultaneously proved that the K adsorption energy of the doped structure is greatly improved. The solid hollow hierarchical porous structure buffers the volume expansion of the potassium insertion process, maintains the original structure after a long cycle and promotes the transfer of potassium ions and electrons. Therefore, the NOP‐PB negative electrode shows extremely enhanced electrochemical performance, including high specific capacity, excellent long‐term stability, and good rate stability.