In situ construction of ball-in-ball structured porous vanadium pentoxide intertwined with carbon fibers induces superior electronic/ionic transport dynamics for aqueous zinc-ion batteries

Advances of Vanadium-based Cathodes forAqueous Zinc Ion Batteries

Aqueous zinc-ion batteries (AZIBs) are promising for energy storage due to their high safety, low cost, and environmental friendliness. Vanadium-based materials, including vanadium oxides, vanadium sulfides, vanadate, and vanadium carbon composites, have gained attention for their diverse crystal structures, multiple oxidation states, and high theoretical capacities. This review summarizes recent advances in vanadium-based cathodes, focusing on structural design and modification strategies, such as amorphous structures, defect engineering, conductive carbon matrices, and cation pre-intercalation to enhance Zn2+ storage. Vanadium oxides and vanadium sulfides offer unique ion diffusion advantages, while vanadate and vanadium carbon composites improve conductivity and stability. Vanadate is highlighted as a critical approach to reduce electrostatic repulsion and facilitate Zn2+ storage. Vanadium carbon composites (V-MOF derivations, vanadium oxides @ carbon, combined with graphene and conductive polymer) have unique advantages in terms of conductivity, ion diffusion, and structural stability. Emerging materials like VN, VOPO₄ and V2CTx are also discussed. Future directions include multi-guest doping, anion pre-intercalation, and advanced carbon integration. This review aims to guide the development of high-performance AZIBs and inspire future research in this field.

How About Vanadium-Based Compounds as Cathode Materials for Aqueous Zinc Ion Batteries?

Aqueous zinc-ion batteries (AZIBs) stand out among many monovalent/multivalent metal-ion batteries as promising new energy storage devices because of their good safety, low cost, and environmental friendliness. Nevertheless, there are still many great challenges to exploring new-type cathode materials that are suitable for Zn2+ intercalation. Vanadium-based compounds with various structures, large layer spacing, and different oxidation states are considered suitable cathode candidates for AZIBs. Herein, the research advances in vanadium-based compounds in recent years are systematically reviewed. The preparation methods, crystal structures, electrochemical performances, and energy storage mechanisms of vanadium-based compounds (e.g., vanadium phosphates, vanadium oxides, vanadates, vanadium sulfides, and vanadium nitrides) are mainly introduced. Finally, the limitations and development prospects of vanadium-based compounds are pointed out. Vanadium-based compounds as cathode materials for AZIBs are hoped to flourish in the coming years and attract more and more researchers' attention.

Status and Opportunities of Zinc Ion Hybrid Capacitors: Focus on Carbon Materials, Current Collectors, and Separators

Zinc ion hybrid capacitors (ZIHCs), which integrate the features of the high power of supercapacitors and the high energy of zinc ion batteries, are promising competitors in future electrochemical energy storage applications. Carbon-based materials are deemed the competitive candidates for cathodes of ZIHC due to their cost-effectiveness, high electronic conductivity, chemical inertness, controllable surface states, and tunable pore architectures. In recent years, great research efforts have been devoted to further improving the energy density and cycling stability of ZIHCs. Reasonable modification and optimization of carbon-based materials offer a remedy for these challenges. In this review, the structural design, and electrochemical properties of carbon-based cathode materials with different dimensions, as well as the selection of compatible, robust current collectors and separators for ZIHCs are discussed. The challenges and prospects of ZIHCs are showcased to guide the innovative development of carbon-based cathode materials and the development of novel ZIHCs.

Tungsten-oxygen bond pre-introduced VO2(B) nanoribbons enable fast and stable zinc ion storage ability

The tunnel structure of the bronze phase vanadium dioxide (VO2(B)) can be used as the zinc ion storage active sites. However, the intense charge repulsion of divalent Zn2+ causes a sluggish reaction kinetics in the tunnel VO2(B). Here, a tungsten-oxygen bond pre-introduced (TOBI) approach is proposed to modulate the tunnel structure of VO2(B). The VO2(B) cathodes with TOBI of 0.5 at% to 3.0 at% have been controllably synthesized by a simple hydrothermal method. The results from structural analysis uncover that the pre-introduced W6+ replaces the V4+ in VO2(B) to form WO6 octahedra. Benefiting from the rapid diffusion kinetics, enhanced structural stability and improved conductivity enabled by the TOBI, the optimal VO2(B) nanoribbons with 1.5 at% shows a high reversible capacity of 265 mAh g-1, a high rate-performance of up-to 10 A g-1 and a long cycling stability of 2000 cycles. Moreover, a pseudo-capacitive dominated Zn2+ intercalation/de-intercalation behavior is solidly determined by the electrochemical kinetics testing and structural characterizations. This TOBI method is referential for developing other multivalent ion battery cathodes with outstanding performances.