Metallic few-layered 1T-VS_(2)nanosheets for enhanced sodium storage

Metallic few-layered 1T phase vanadium disulfide nanosheets have been employed for boosting sodium ion batteries.It can deliver a capacity of 241 mAh∙g^(−1)at 100 mA∙g^(−1)after 200 cycles.Such long-term stability is attributed to the facile ion diffusion and electron transport resulting from the well-designed two-dimensional(2D)electron-electron correlations among V atoms in the 1T phase and optimized in-planar electric transport.Our results highlight the phase engineering into electrode design for energy storage.

Oxygen vacancies enriched nickel cobalt based nanoflower cathodes: Mechanism and application of the enhanced energy storage

The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge. Herein, we synthesize nickel cobalt-based oxides nanoflower arrays assembled with nanowires grown on Ni foam via the hydrothermal process followed annealing process in air and argon atmospheres respectively. It is found that the annealing atmosphere has a vital influence on the oxygen vacancies and electronic microstructures of resulting NiCo_(2)O_(4) (NCO-Air) and CoNiO_(2) (NCO-Ar) products, which NCO-Ar has more oxygen vacancies and larger specific surface area of 163.48 m^(2)/g. The density functional theory calculation reveals that more oxygen vacancies can provide more electrons to adsorb –OH free anions resulting in superior electrochemical energy storage performance. Therefore, the assembled asymmetric supercapacitor of NCO-Ar//active carbon delivers an excellent energy density of 112.52 Wh/kg at a power density of 558.73 W/kg and the fabricated NCO-Ar//Zn battery presents the specific capacity of 180.20 mAh/g and energy density of 308.14 Wh/kg. The experimental measurement and theoretical calculation not only provide a facile strategy to construct flower-like mesoporous architectures with massive oxygen vacancies, but also demonstrate that NCO-Ar is an ideal electrode material for the next generation of energy storage devices.

Roadmap of amorphous metal-organic framework for electrochemical energy conversion and storage

Metal-organic frameworks(MOFs),a well-known coordination network involving potential voids,have attracted attention for energy conversion and storage.As far as is known,MOFs are not only believed to be crystalline.Emerging amorphous MOFs(aMOFs)are starting as supplementary to crystalline MOF(cMOF)in various electrochemical energy fields owing to intrinsic superiorities over crystalline states,greater ease of processing,and distinct physical and chemical properties.aMOFs retain the basic skeletons and connectivity of building units but without any long-range order.Such structural features over long range possess the isotropy without grain boundaries,resulting in fast ions flux and uniform distribution.Simultaneously,distinct shortrange characteristics provide diverse pore confined environment and abundant active sites,and thus accelerate mass transport and charge transfer during electrochemical reactions.Deep understandings and controllable design of aMOF may broaden the opportunities for both scientific researches beyond crystalline materials and practical applications.To date,comprehensive reviews about aMOFs in the fields of energy conversion and storage remain woefully underrepresented.Herein,we summarize the roadmap of aMOF from the development,structural design,opportunity,application,bottleneck,and perspective.In-depth structure-activity relationships with aMOF chemistry are highlighted in the typical electrochemical energy conversion like water oxidation and energy storage,including supercapacitor and battery.The combination of disordered nature at long range and short range,alongside the dynamic structural changes,is promising to reinforce cognition of aMOF domains with MOF versatility,shedding light on the design for efficient electrochemical energy applications via amorphization.