The key concern in constructing high-energy supercapacitors is maximizing the electrode capacitance and the cell voltage. However, the current research usually addresses this issue by designing advanced electrodes or seeking high-potential electrolytes separately, instead of both. Herein, we demonstrate a two-pronged design of ternary-doped carbon electrodes and a high-voltage “water-in-salt” (WIS) gel electrolyte to support advanced aqueous-based solid-state supercapacitors. The fabrication of N/S/O multidoped carbons is quite straightforward, involving a facile benzoquinone/sulfourea polymerization and a common carbonization/activation procedure, which avoid sophisticated technique/conditions and/or time-consuming synthetic routes. The carbons feature an extraordinary surface area, high content of heteroatoms, and improved surface wettability. A highly porous gel polymer is introduced as a supporting matrix for the WIS to design a 2.3 V gel-type electrolyte, in pursuit of a new record high-energy aqueous solid-state supercapacitor of 37.7 W h kg⁻¹, with excellent temperature robustness in the range of 0–80 °C. Furthermore, an assembled flexible device delivers a stable energy output of 34.3 W h kg⁻¹ and demonstrates great flexibility with 91.6% energy retention even in a bending state of 180°. This study presents an electrode/electrolyte cooperative effect to unlock the energy potential of aqueous flexible solid-state supercapacitors.

N/O self-doped hollow carbon nanorods (HCNs) with micro/mesoporous walls are fabricated based on a new deep-eutectic-solvent that serves as an all-in-one precursor, self-template, and self-dopant agent. The carbon-based supercapacitor using an ionic liquid electrolyte exhibits a high energy density of 116.5 W h kg⁻¹ with excellent long-term cycling performance.

MgH₂/single-atom heterojunction systems were designed with improved dehydrogenation performance for hydrogen storage applications.

Quinones are highly redox-active due to their remarkable electron transfer kinetics and electrochemical reversibility, and amines credited with exceptional electron-pair donicity can strengthen the redox kinetics of quinones and simultaneously incorporate electroactive nitrogen species. Herein, a universal route based on benzoquinone and amines with different chemical structures is developed to engineer O/N codoped porous carbons. This approach drives the designability of high-surface-area carbons with tailored geometries (nanosphere, nanofiber, granule and honeycomb), ensuring fast ion/electron transport kinetics to support electrical double layer capacitance. Besides, highly redox-active O/N heteroatoms trigger remarkable pseudocapacitance via reversible faradaic reactions of benzoquinone/hydroquinone transformation and pyridinic/pyrrolic nitrogen response in a H₂SO₄ electrolyte. Consequently, a representative supercapacitor achieves greatly enhanced electrochemical reaction dynamics, yielding an extraordinary energy density (18.2 W h kg⁻¹), ultralong stability and excellent high-rate features (90.1% energy retention over 100 000 successive cycles at 20 A g⁻¹). The enhanced wetting compatibility of carbon surfaces/electrolyte ions resulting from O/N doping can further extend the carbon electrodes to water-in-salt, organic and ionic liquid electrolytes for constructing high energy supercapacitors (up to 90.6 W h kg⁻¹). This work provides a general guidance to design high-performance carbons toward efficient energy storage.

Electrochemical conversion of nitrate (NO₃⁻) to ammonia (NH₃) is a potential way to produce green NH₃ and remediate the nitrogen cycle. In this paper, an efficient catalyst of spherical CuO made by stacking small particles with oxygen‐rich vacancies is reported. The NH₃ yield and Faraday efficiency are 15.53 mg h⁻¹ mg_cat⁻¹ and 90.69%, respectively, in a neutral electrolyte at a voltage of ‐0.80 V (vs. reversible hydrogen electrode). The high activity of the electrodes results from changes in the phase and structure during electrochemical reduction. Structurally, there is a shift from a spherical structure with dense accumulation of small particles to a layered network structure with uniform distribution of small particles stacked on top of each other, thus exposing more active sites. Furthermore, in terms of phase, the electrode transitions from CuO to Cu/Cu(OH)₂. Density functional theory calculations showed that Cu(OH)₂ formation enhances NO₃‐ adsorption. Meanwhile, the Cu(OH)₂ can inhibit the competing hydrogen evolution reaction, while the formation of Cu (111) crystal surfaces facilitates the hydrogenation reaction. The synergistic effect between the two promotes the NO₃‐ to NH₃. Therefore, this study provides a new idea and direction for Cu‐based oxides in electrocatalytic NH₃ production.