With the continuing demand for clean and sustainable energy storage devices, aqueous magnesium-ion capacitors have gained prominence as a viable electrochemical solution. However, high-performance aqueous magnesium-ion storage devices for energy need to satisfy rigorous requirements due to the large hydrated ionic radius of Mg²⁺ cations and the structural collapse of host materials during insertion/extraction. Herein, we propose a fluorine-mediated structural regulation strategy to design fluorine-mediated multivalent manganese oxide (F-m-MnO_x) as cathode materials. By partially substituting oxygen sites with fluorine atoms, high-strength Mn–F bonds are formed within the MnO₂ lattice, which locally enhance the framework stability by reinforcing the tunnel structure and effectively suppressing structural degradation during cycling. Furthermore, the robust Mn–F bond energy enables a unique “pinning effect” anchoring hydrothermally synthesized KMnF₃ nanoparticles onto the MnO₂ matrix. These KMnF₃ nanoparticles act as dynamic bridges during Mg²⁺ insertion/extraction processes, with their surface-exposed chemically active sites facilitating transient yet reversible interactions with migrating Mg²⁺ ions. This innovative design significantly enhances Mg²⁺ diffusion kinetics through the bulk phase, offering a groundbreaking mechanism to overcome the inherent sluggish ion transport in multivalent cation systems. The F-m-MnO_x cathode delivers exceptional performance metrics: a high specific capacity of 142 mAh/g at 0.1 A/g, outstanding cycling stability (89.6% retention after 1800 cycles), and rapid kinetics. This research not only establishes an innovative design concept for advanced electrode materials through halogen-mediated structural engineering but also elucidates the dual magnesium-ion storage mechanism involving both KMnF₃ and MnO₂ in F-m-MnO_x through ex-situ characterization, enabling new possibilities for future clean energy storage.

Aqueous zinc-iodine batteries (AZIBs) have attracted significant attention as the most promising next-generation energy storage technology due to their low cost, inherent safety, and high energy density. However, their practical application is hindered by the poor electronic conductivity of iodine cathodes and the severe shuttling effect of intermediate polyiodides. Here, we report a novel micropores carbon framework (MCF) synthesized from waste coffee grounds via a facile carbonization-activation process. The resultant MCF features an ultrahigh specific surface area and a high density of micropores, which not only physically confine iodine species to minimize iodine loss but also enhance the electronic conductivity of the composite cathode. Furthermore, biomass-derived heteroatom dopings (nitrogen functionalities) facilitate effective chemical anchoring of polyiodide intermediates, thereby mitigating the shuttle effect. UV–visible spectroscopy and electrochemical kinetic analyses further confirm the rapid transformation and inhibition mechanism of iodine species by MCF. Consequently, the MCF/I₂ cathode delivers superior specific capacities of 238.3 mA h g⁻¹ at 0.2 A g⁻¹ and maintains outstanding cycling performance with a capacity retention of 85.2% after 1200 cycles at 1.0 A g⁻¹. This work not only provides an important reference for the design of high-performance iodine-host porous carbon materials but also explores new paths for the sustainable, high-value utilization of waste biomass resources.

Electrochemical CO₂ reduction reaction (CO₂RR) is a promising process for reducing CO₂ emissions and producing high-value chemicals. However, this process remains hindered by diffusion-limited mass transfer, low activity, and high overpotentials. Here, we controllably prepared hierarchically porous nitrogen-doped carbon, carbon nanosheets, and carbon nanotubes confined single-atom Fe catalysts for electrochemical CO₂ reduction. The hierarchically porous Fe-N-C (Fe-HP) exhibited prominent performance with a Faradaic efficiency of CO (FE_CO) up to 80% and a CO partial current density (j_CO) of −5.2 mA·cm⁻² at −0.5 V vs. reversible hydrogen electrode (RHE), far outperforming the single-atom Fe on N-C nanosheets (Fe-NS) and N-C nanotubes (Fe-NT). The detailed characterizations and kinetic analysis revealed that the hierarchically porous structure accelerated the mass transfer and electron transfer processes toward single-atom Fe sites, promoting the desorption of CO and thereby enhancing CO₂ reduction efficiency. This study provides a promising approach to designing efficient single-atom catalysts with porous structures for energy conversion applications.

The advancement of aqueous magnesium ion energy storage devices encounters limitations due to the substantial hydration radius of magnesium ions (Mg²⁺) and their strong electrostatic interaction with the primary material. Consequently, this study successfully developed a MnS/MnO heterostructure through a straightforward hydrothermal and annealing method, marking its initial application in aqueous magnesium ion capacitors (AMICs). The fabricated MnS/MnO heterostructure, characterized by S defects, also generates Mn defects via in-situ initiation of early electrochemical processes. This unique dual ion defects MnS/MnO heterostructure (DID-MnS/MnO) enables the transformation of MnS and MnO, initially not highly active electrochemically for Mg²⁺, into cathode materials exhibiting high electrochemical activity and superior performance. Moreover, DID-MnS/MnO enhances conductivity, improves the kinetics of surface redox reactions, and increases the diffusion rate of Mg²⁺. Furthermore, this study introduces a dual energy storage mechanism for DID-MnS/MnO, which, in conjunction with dual ion defects, offers additional active sites for Mg²⁺ insertion/deinsertion in the host material, mitigating volume expansion and structural degradation during repeated charge-discharge cycles, thereby significantly enhancing cycling reversibility. As anticipated, using a three-electrode system, the developed DID-MnS/MnO demonstrated a discharge specific capacity of 237.9 mAh/g at a current density of 0.1 A/g. Remarkably, the constructed AMIC maintained a capacity retention rate of 94.3% after 10000 cycles at a current density of 1.0 A/g, with a specific capacitance of 165.7 F/g. Hence, DID-MnS/MnO offers insightful perspectives for designing alternative clean energy sources and is expected to contribute significantly to the advancement of the clean energy sector.

Aqueous supercapacitors (SCs) have been regarded as a promising candidate for commercial energy storage device due to their superior safety, low cost, and environmental benignity. Unfortunately, an age-old challenge of achieving both long electrode lifespan and qualified energy-storage property blocks their practical application. Herein, we develop an electrode-electrolyte integrated optimization strategy to fulfill the real-life device requirements. Electrode optimization simultaneously regulates the nanomorphology and surface chemistry of the tungsten oxide anode, resulting in superior electrochemical performance given by an ideal “bird-nest” structure with optimal oxygen vacancy status; the anodes interact with and are protected from dissolution and structural collapse by the rationally designed hybrid electrolyte with optimized pH and facilitated cation desorption behavior. Collaboratively, a record-breaking durability of no capacitive decay after 250000 cycles is achieved. On the basis of this integrated optimization, the first aqueous pouch SCs with real-life practicability were manufactured by a soft-package encapsulation technique, which can steadily power commercial 3 C products such as tablets and smartphones and maintain safely working against extreme conditions. This work demonstrates the possibility of using aqueous energy storage devices with enhanced safety and lower cost to replace the commercial organic counterparts for wide range of daily applications.

N₂ electroreduction reaction (NRR) offers a feasible and promising alternative for NH₃ production by using clean energy sources. However, it is still obstructed by the pretty low NH₃ yield rate and Faradaic efficiency (FE) primarily due to the undesired competing hydrogen evolution reaction and the extremely stable N≡N bond. Herein, bismuth nanoparticles were successfully embedded in N and P co-doped carbon nanoflakes (Bi/NPC) by high-temperature pyrolyzation of Bi-zeolitic imidazole frameworks (ZIF) followed by phosphorization, and used as a high-efficiency catalyst toward N₂ electroreduction to NH₃. In 0.1 M KHCO₃ electrolyte, Bi/NPC exhibits excellent NRR performances, including a high NH₃ yield rate of 3.12 µg·h⁻¹·cm⁻² (−0.6 V vs. reversible hydrogen electrode (RHE)), an outstanding FE of 13.58% (−0.4 V vs. RHE), and a remarkable stability up to 36 h under ambient conditions. This outstanding NRR catalytic activity is mainly attributed to the intrinsic electrocatalytic NRR activity combined with the inert hydrogen evolution reaction (HER) activity of Bi, the adsorption and activation of N₂ facilitated by N dopants, as well as the superior conductivity and the large specific surface area of the two-dimensional layered carbon matrix. Notably, the hydrogen source provided by P dopant promotes the hydrogenation of the adsorbed N, which further boosts the NRR performance in alkaline electrolyte. The ultralong durability of Bi/NPC is attributed to the highly dispersed bismuth catalytic active centers confined in the skeleton of N and P co-doped carbon nanoflakes, which inhibits the agglomeration of bismuth centers. This work presents a novel avenue for designation and fabrication of high-performance Bi-based electrocatalysts for NRR.

Supported single-atom catalysts (SACs) possess high catalytic activity, selectivity, and atom utilizations. However, the atom coordination environments of SACs are difficult to accurately regulate due to the high complexity of coordination site and local environment of support. Herein, we develop an in-situ electrochemical cation-exchange method to fill the cation vacancies in MnO₂ with Ru single atoms (SAs). This obtained catalyst exhibits high mass activity, which is ~ 44 times higher than commercial RuO₂ catalyst and excellent stability, superior to the most state-of-the-art oxygen evolution reaction (OER) catalysts. The experimental and theoretical results confirm that the doped Ru can induce charge density redistribution, resulting in the optimized binding of oxygen species, and the strong covalent interaction between Ru and MnO₂ for resisting oxidation and corrosion. This work will provide a new concept in the synthesis of well-defined local environments of supported SAs.