Xin Cai

Transition‐metal sulfide‐based electrocatalysts hold great promise for the advancement of various renewable energy technologies, yet their complex in situ surface reconstruction during electrochemical operation remains a significant challenge. Herein, we report a highly efficient binder‐free bifunctional electrocatalyst, FeS/CoS _1.097 @NC, consisting of cobalt‐iron sulfide polyhedra encapsulated within nitrogen‐doped carbon nanorods directly grown on carbon cloth. The judiciously designed FeS/CoS _1.097 @NC architecture features abundant active sites, moderate wettability, and reinforced electronic synergy, which collectively facilitate interfacial charge transfer and redox kinetics. As a bifunctional catalyst, FeS/CoS _1.097 @NC realizes a low overall overpotential of 0.6 V, comparable to that of the Pt/C+RuO ₂ benchmark. Combined experimental and theoretical investigation unravels that the in situ electrochemical reconstruction process promotes the formation and stabilization of Co‐Fe (oxy)hydroxides as the dominant active phase. Notably, the reconstructed hybrid phases effectively modulate the d ‐band center and optimize the binding affinity of active sites toward (oxy) intermediates, thereby enhancing both oxygen evolution reaction (OER)/oxygen reduction reaction (ORR) kinetics and long‐term durability. When employed as a free‐standing air‐cathode, FeS/CoS _1.097 @NC endows rechargeable and flexible Zn‐air batteries with high discharge capacities, superb rate capability and robust operational durability upon cycling. This work envisions a promising approach to constructing high‐efficiency hetero‐structured electrocatalysts toward multifunctional catalysis and portable/wearable energy devices.

Photoassisted aqueous zinc batteries provide a compact route to couple light input with electrochemical energy storage, but the ionic origin of light-enhanced capacity remains difficult to quantify because proton and zinc-ion storage pathways are strongly intertwined. Here, a self-supported Cu/Cu₂S nanoarray is used as a light-responsive conversion interface to resolve illumination-regulated H⁺/Zn²⁺ partitioning. By tuning proton accessibility through dimethylformamide, H₂O/dimethylformamide, and H₂O electrolyte matrices, the dominant charge carrier shifts from Zn²⁺-favored storage to nearly balanced H⁺/Zn²⁺ storage and then to H⁺-dominated storage. Illumination enlarges the cyclic voltammetry response by 110.2%, reduces polarization, and enables nearly 50% capacity enhancement at 5 A g^-1. State-resolved Raman spectroscopy, X-ray photoelectron spectroscopy, and ex situ X-ray diffraction reveal light-regulated ZnS/basic-zinc-salt evolution and improved Cu/S interfacial reversibility. These findings identify nanoscale Cu-S conversion interfaces as light-tunable platforms for directing proton-cation competition, offering a carrier-resolved design principle for photoassisted aqueous batteries.

Developing high-efficiency interlayer catalysts is a promising tactic for improving the cycling performance of rechargeable lithium–sulfur (Li–S) batteries. Herein, using the Prussian blue analogue as the precursor, cobalt–zinc carbide nanocrystal-embedded N-doped porous carbon (Co₃ZnC@NC) is synthesized via simple post-carbonization. The obtained Co₃ZnC@NC nanospheres exhibit a robust core–shell structure showing good conductivity, high porosity and available metal active sites, favoring the interfacial charge transfer and the electron transport upon electrochemical reactions. The results demonstrate that the Co₃ZnC@NC catalyst is quite suitable for boosting the adsorption and redox conversion kinetics of soluble polysulfides. When acting as the separator interlayer, Co₃ZnC@NC contributes to improved Li–S batteries with a high discharge specific capacity of 1659.8 mA h g⁻¹ at 0.1C and superior cycling stability of over 250 cycles at 1.0C (high capacity retention of 84.1% after 100 cycles at 0.5C). Furthermore, the Co₃ZnC@NC-based battery can maintain a high discharge capacity of 734.0 mA h g⁻¹ at 5.0C, along with delivering a stable reversible capacity of 805.4 mA h g⁻¹ (∼5 mA h cm⁻²) after 50 cycles even under a high sulfur loading of 6.2 mg cm⁻². This study affords a viable way to construct highly dispersed bimetal/carbon composites for efficient catalysts and renewable energy devices.

Herein, Cu-foam-supported CuO nanowire arrays covered with Cu₂S nanosheet substrates (Cu/CuO/Cu₂S) are adopted as efficient photoelectrodes for photorechargeable lithium-ion batteries (PR-LIBs). The assembled PR-LIB exhibits remarkable solar energy conversion efficiency alongside superior lithium storage capabilities. Without an electrical power supply, the photocharged PR-LIB sustained a discharge process for 63.0 h under a constant current density of 0.05 mA cm^-2. The corresponding solar-to-electrical energy conversion efficiency is 4.50%, which is an impressive achievement among recently reported contemporary technologies. Mechanism investigation shows that the Cu/CuO/Cu₂S photogenerated carriers augment the extraction and insertion of Li⁺ according to different oxidation and reduction reactions in the charging and discharging reactions. This research delineates a refined model system and proposes innovative directions for developing efficient heterojunction photoelectrodes, significantly propelling the development of PR-LIB technology.

The cycling stability of ball milled silicon/graphene composite can be improved by an interlayer of Al₂O₃ nanoparticles for lithium storage.

Sufficient integration of multiple active moieties and correlated heterostructure engineering are pivotal to optimize the reaction kinetics and the intrinsic activities of heterogeneous electrocatalysts. Herein, an integrated heterostructure of biphasic nanoalloys are constructed, encasing in in situ grown and interlaced nitrogen‐doped carbon nanoflake arrays (CoFe‐NiFe/NC). Well‐designed CoFe‐NiFe/NC owns more accessible active sites and interfacial conjugation effects, jointly accelerating the electron transfer and mass transport for multifunctional electrocatalysis. Such unconventional monolith delivers extraordinary trifunctional activities for hydrogen evolution reaction, oxygen evolution reaction (overpotential of 185 mV at 10 mA cm⁻²) and oxygen reduction reaction. The superior trifunctionality of CoFe‐NiFe/NC is rationalized with experimental and theoretical elucidation. Results reveal that the modulated electronic synergism between the Ni, Fe‐assisted Co sites and the adjacent N‐bridged carbon matrix decisively favors the appropriate binding of intermediates for promoted redox kinetics. Consequently, stand‐alone CoFe‐NiFe/NC cathode contributes to high‐performance aqueous/flexible zinc‐air batteries (ZABs), exhibiting high power/specific energy and excellent cycling stability. Remarkably, CoFe‐NiFe/NC‐based alkaline water electrolyzer requires merely 1.51 V to reach 10 mA cm⁻², and a self‐driven water splitting system yields a high H₂ evolution rate. This unique heterostructure monolith would open up opportunities for developing high‐efficiency multifunctional catalysts and advanced energy utilization devices.