Enhanced electrochemical performance of W incorporated VO2 nanocomposite cathode material for lithium battery application

Manganese Intercalation Enabling High-Performance Aqueous Fe-VO2 Batteries

The aqueous iron ion batteries (AIIBs) are an attractive option for large-scale energy storage applications. However, the inadequate plating and stripping of Fe2+ ions underscore the need to explore more suitable cathode materials. Herein, we optimize the structure of tunnel-like VO2 nanosheets by introducing Mn2+ ion intercalation as a cathode material to enhance their performance in AIIBs. Mn2+ serves as a stabilizing pillar for VO2, which brings some oxygen vacancies to provide extra electrochemically active sites, and accelerates the reversible (de)insertion of Fe2+ ions. In addition, the density functional theory (DFT) calculations show that the introduction of Mn2+ reduces the band gap of VO2 and also decreases the electrostatic interaction between Fe2+ and VO2. Consequently, the VO2 with interlayer Mn2+ pillars (5% MVO) electrodes exhibit a remarkable capacity of 284.32 mAh g-1 at a current density of 0.1 A g-1 and demonstrate excellent cycle life, maintaining 81.7% of their capacity at 1.0 A g-1 after 600 cycles. Therefore, these results offer a promising choice for the cathode material to achieve outstanding electrochemical performance in AIIBs.

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.

Green Synthesis of Metal Nanoparticles and their Applications in Different Fields: A Review

Nanotechnology is an art for application and handling of materials at very small scales i.e. 1–100 nm. The materials at this scale exhibit significantly different properties compared to same materials at larger scales. There are so many physical and chemical methods for the synthesis of nanoscale materials but the most appropriate are the ones that synthesize materials using green chemistry eco-friendly techniques. Recently, the collaboration between nanotechnology and biology has opened up new horizons of nanobiotechnology that integrates the use of biological materials in a number of biochemical and biophysical processes. This approach has significantly boosted up nanoparticles (NPs) production without employing harsh and toxic conditions and chemicals. This review is aimed to provide an outline of latest developments in synthesis of NPs through biotic entities and their potential applications.