Vanadium Dioxide Cathodes for High-Rate Photo-Rechargeable Zinc-Ion Batteries

Photovoltaics are an important source of renewable energy, but due the intermittent nature of insolation, solar cells usually need to be connected to rechargeable batteries, electrochemical capacitors or other energy storage devices, which adds to the complexity and cost of these systems. In this work, we report a cathode design for photo-rechargeable zinc-ion batteries (photo-ZIBs) that is inherently capable of harvesting sunlight to recharge without the need for external solar cells. The proposed photocathodes comprising a composite of vanadium dioxide nanorods and reduced graphene oxide, are engineered to provide the necessary charge separation and storage for photocharging under illumination. The photo-ZIBs achieve gravimetric capacities of ~ 282 mAh g-1 in the dark and ~ 315 mAh g-1 under illumination, at 200 mA g-1, demonstrating the use of light not only to charge the deceives, but additionally to enhance their capacity. The photo-ZIBs also demonstrate enhanced high-rate capabilities under illumination, as well as a capacity retention of ∼ 90% over 1000 cycles. The proposed photo-ZIBs demonstrate a promising new technology for addressing energy poverty, due to their high performance and inherent cost-efficiency and safety.Newton International Fellowship-Royal Society (UK) grant NIF∖R1∖181656 ERC Consolidator grant MIGHTY - 866005 EPSRC Graphene CDT EP/L016087/

Influence of charge traps in carbon nanodots on gas interaction

The nonlinear electrical characteristic of carbon nanodots (CNDs) has revealed important physical phenomena of charge trapping playing a dominant role in surface interactions. Functional groups on the surface of CNDs attract ambient water molecules which in turn act as charge traps and give rise to electrical hysteresis that plays a dominant role in understanding charge transport in CNDs on surface interactions. Hysteresis in the current-voltage response is further utilized to study the interaction of the CNDs with nitrogen dioxide gas as an external stimuli. The hysteresis area is observed to be dependent on the time of gas interaction with the CNDs, therefore revealing the interaction mechanism of the CNDs with the gas

In Situ and Operando Analyses of Reaction Mechanisms in Vanadium Oxides for Li-, Na-, Zn-, and Mg-Ions Batteries

Due to their diversity in the composition, lattice structures and physical/chemical properties and various oxidation states (2+, 3+, 4+ and 5+), (VxOy) nanomaterials have attached much attention for developing new rechargeable batteries, including lithium-ion batteries (LIBs), sodium-ion batteries (NIBs), zinc-ion batteries (ZIBs) and magnesium-ion batteries (MIBs) as well as new energy storage concepts such as light-rechargeable batteries. However, to further improve the electrochemical performance of VxOy based batteries, it is crucial to understand the various electrochemical mechanisms taking place in these materials for LIBs, NIBs, ZIBs and MIBs. This review covers a systematical discussion of in-situ and operando analysis methods carried out on V2O5, VO2, LixVyOz, NaxVyOz, ZnxVyOz and MgxVyOz for LIBs, NIBs, ZIBs and MIBs and the fundamental insights they have provided in the energy storage mechanisms in these batteries.EPSRC funding, (EP/T015179/1

Vanadium Dioxide Cathodes for High-Rate Photo-Rechargeable Zinc-Ion Batteries

Photovoltaics are an important source of renewable energy, but due to the intermittent nature of insolation, solar cells usually need to be connected to rechargeable batteries, electrochemical capacitors or other energy storage devices, which adds to the complexity and cost of these systems. In this work, a cathode design for photo-rechargeable zinc-ion batteries (photo-ZIBs) is reported, that is inherently capable of harvesting sunlight to recharge without the need for external solar cells. The proposed photocathodes, comprising a composite of vanadium dioxide nanorods and reduced graphene oxide, are engineered to provide the necessary charge separation and storage for photocharging under illumination. The photo-ZIBs achieve capacities of ≈282 mAh g−1 in the dark and ≈315 mAh g−1 under illumination, at 200 mA g−1, demonstrating the use of light not only to charge the devices, but additionally to enhance their capacity. The photo-ZIBs also demonstrate enhanced high-rate capabilities under illumination, as well as a capacity retention of ≈90% over 1000 cycles. The proposed photo-ZIBs are considered a promising new technology for addressing energy poverty, due to their high performance and inherent cost-efficiency and safety