Phase engineering has gained significant attention in energy-storage applications due to its ability to tailor the physicochemical properties and functionalities of electrode materials. In this study, we demonstrate the in-situ partial phase conversion of niobium pentoxide (Nb₂O₅), resulting in the formation of a monoclinic/orthorhombic (H/T-Nb₂O₅) heterophase homojunction. This study further confirms that the unique heterophase interface plays a crucial role in regulating the local electronic environment, resulting in charge redistribution, the formation of an internal electric field, and enhanced electron transfer. Moreover, the presence of abundant phase interfaces offers additional reactive sites for Li⁺ ion adsorption, thereby enhancing reaction dynamics. The synergistic effects within the H/T-Nb₂O₅ homojunction are reflected in its high Li⁺ storage capacity (413 mAh g⁻¹ at 100 mA g⁻¹), superior rate capability, and cycling stability. Thus, this study demonstrates that the construction of heterophase homojunctions offers a promising strategy for developing high-performance anode materials for efficient Li-ion storage.

Interfacial engineering, particularly the design of artificial solid-electrolyte interphases (SEIs), has been successfully applied in all-solid-state batteries (ASSLBs) for industrial applications. However, a fundamental understanding of the synthesis and mechanism models of artificial SEIs in all-solid-state Li-ion batteries remains limited. In this review, recent advances in designing and synthesizing artificial SEIs for ASSLBs to solve interfacial issues are thoroughly discussed, covering three main preparation methods and their technical routes: 1) atomic layer deposition, 2) sol-gel methods, and 3) mechanical ball-milling methods. Moreover, advanced ex-situ characterization techniques for artificial SEIs are comprehensively summarized. Finally, this review provides perspectives on techniques for the interface engineering of artificial SEIs for ASSLBs, with focus on promising methods for industrial applications.

The use of lithium-ion batteries in portable electronic devices and electric vehicles has become well-established, and battery demand is rapidly increasing annually. While technological innovations in electrode materials and battery performance have been pursued, the environmental threats and resource wastage posed by the resulting surge in used batteries have been overlooked. Spent batteries are technically inoperable but contain excess metal inside the structure, making recycling essential for environmental protection and recovery of scarce resources. The battery recycling industry has gradually emerged under the influence of government implementation and ecological protection trends. However, the annual recycling volume is still insufficient compared to the output volume of used batteries. Therefore, more recycling plants and advanced technologies are imperative to improve recycling efficiency. This article summarizes pretreatment, pyrometallurgical, and hydrometallurgical processes and technologies in three major parts, analyzes their applicability and environmental friendliness using industrial examples, highlights their technical shortcomings and problems, and emphasizes the bright future of battery recycling.

Transition metal oxides hold promise as electrode materials for energy-storage devices such as batteries and supercapacitors. However, achieving ideal electrode materials with high capacity, long-term cycling stability, and superb rate capability remains a challenge. In this study, we present a self-assembled heterogeneous structure consisting of TiO₂ nanosheets derived from Ti₃C₂T_x MXene and reduced graphene oxide. This structure facilitates the formation of heterogeneous structures while establishing a conductive network. The restacking of porous TiO₂ nanosheets and reduced graphene oxide within the heterostructure results in high porosity and excellent conductivity. Due to enhanced electron and Na⁺ transfer, as well as improved structural stability during the Na⁺ insertion/extraction process, this heterogeneous structure exhibited exceptional Na⁺ storage performance. Specifically, it exhibits a long-term cycling stability (217 mAh g⁻¹ at 10 C, 5000 cycles) and an ultrahigh rate capability (135 mAh g^-1, 40 C). Analysis of electrode reaction kinetics suggests that Na⁺ storage in the heterostructure is predominantly governed by a surface-controlled process. Our results provide a promising strategy for utilizing self-assembled heterostructures in advanced energy storage applications.

Positive electrodes play a decisive role in exploring the Zn²⁺ storage mechanism and improving the electrochemical performance of aqueous Zn-ion batteries (AZIBs). Feasible design and preparation of cathode materials have been crucial for AZIBs in recent years. Herein, taking the advantage of the tunnel structure of VO₂, which can withstand volume change during charging/discharging, VO₂ doped with Ce ions is synthesized by a simple one-step hydrothermal method and oxygen vacancies are synchronously generated during synthesis. It delivers a capacity of 158.5 mAh g⁻¹ at the current density of 5 A g⁻¹ after 1000 cycles and exhibits an excellent energy density of 312.8 Wh kg⁻¹ at the power density of 142 W kg⁻¹. The structural modification and prospect of enhancing its conductivity by doping with rare-earth metals and introducing oxygen vacancies may aid in improving the stability of AZIBs in the future.

Carbon-loaded metal nanoparticles (NPs) are widely employed as functional materials for electrocatalysis. In this study, a rapid thermal shock method was developed to load various metal nanoparticles onto carbon supports. Compared to conventional pyrolysis processes, Joule heating enables rapid heating to elevated temperatures within a short period, effectively preventing the migration and aggregation of metal atoms. Simultaneously, the anchoring effect of defective carbon carriers ensures the uniform distribution of NPs on the carbon supports. Additionally, nitrogen doping can significantly enhance the electronic conductivity of the carbon matrix and strengthen the metal-carbon interactions, thereby synergistically improving catalyst performance. When used as electrocatalysts for electrocatalytic CO₂ reduction, bismuth-, indium-, and tin/carbon-carrier-based catalysts exhibit excellent Faraday efficiencies of 92.8%, 86.4%, and 73.3%, respectively, for formate generation in flow cells. The influence of different metals and calcination temperatures on catalytic performance was examined to provide valuable insights into the rational design of carbon-based electrocatalysts with enhanced electrocatalytic activity.

Efficient and stable Pt-free electrocatalysts for oxygen reduction reaction (ORR) are indispensable for future fuel cells. Herein, we describe a heterostructure of Pd nanocrystals (PdNCs) on N-doped Ag nanowires (NWs) synthesized using a direct epitaxial growth strategy with a Pd loading of only 9.5 wt.%. The PdAg bimetallic heterostructure showed the highest mass activity among reported PdAg-based ORR electrocatalysts and exhibited excellent stability, with only a 1.5 mV decay in the half-wave potential even after 20000 cycles of continuous testing. The remarkably enhanced activity and durability can be attributed to the distinct advantages of the ultrasmall PdNCs, cocatalysts of N-doped AgNWs, and their heterointerfaces. This work reveals that the epitaxial growth of a heterostructure on a stable support is a promising strategy for promoting catalytic performance.

Metal-cation doping is a fundamental strategy for enhancing catalyst performance. Fe-doped Ni_0.85Se/NF (Fe-Ni_0.85Se/NF) nanoparticles were prepared at 80 °C via Fe²⁺ etching method. The addition of Fe altered the coordination environment of the Ni species along with the catalyst's morphology, creating additional active sites. Notably, the synergistic interaction between the bimetallic components augmented the built-in activity and accelerated reaction kinetics. The Fe-Ni_0.85Se/NF electrocatalysts demonstrated remarkable catalytic activity for the oxygen evolution reaction (OER), with an acceptable overpotential of 276 mV and a Tafel slope of 58.1 mV dec⁻¹ at 100 mA cm⁻². Moreover, they demonstrated exceptional durability. In situ Raman and X-ray photoelectron spectroscopy (XPS) analyses showed that the excellent OER performance stemmed from the reconstruction-induced hydroxyl oxide. This study offers a novel approach for streamlining the synthesis procedures and reducing the experimental costs for developing high-efficiency electrocatalysts.

Most surface-enhanced Raman scattering (SERS) substrates are based on noble metals or transition metal semiconductors. Developing nonmetallic SERS substrates is of great significance for expanding the application scope of SERS substrate materials. In this study, ultrathin C₆₀ nanosheets with two-dimensional structures were synthesized using CVD and used as SERS substrates. Owing to the combined effects of favorable factors such as the expanded specific surface area and matched interfacial charge transport paths, the substrate has a minimum detection limit of 10⁻¹¹ for rhodamine 6G and a Raman enhancement factor of 10⁷. In addition, the C₆₀ nanosheets exhibited good stability and uniformity as SERS substrates.