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Here we present novel (Mg0.2Ti0.2Zn0.2Cu0.2Fe0.2)3O4 materials prepared via one-step solid state reaction method and subsequently high-energy ball-milling. When used as anodes for LIBs, it exhibits superior lithium storage properties.

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Aqueous rechargeable zinc ion batteries are promising candidates for grid-scale applications owing to their low cost and high safety. However, they are plagued by the lack of suitable cathode and anode materials. Herein, we report on potassium vanadate (KVO) nanobelts as a promising cathode for an aqueous zinc ion battery, which shows a high discharge capacity of 461 mA h g −1 at 0.2 A g −1 and exhibits a capacity retention of 96.2% over 4000 cycles at 10 A g −1 . Furthermore, to enhance the energy efficiency in an aqueous zinc ion battery, a facile and effective method on the anode is demonstrated. The energy efficiency increases from 47.5% for Zn//KVO coupled with the zinc foil anode to 66.5% for AB-Zn//KVO coupled with an acetylene black film improved zinc foil anode at 10 A g −1 . The remarkable electrochemical performance makes AB-Zn//KVO a strong candidate for a high-performance aqueous zinc ion battery.

Ultrafine crystalline materials have been extensively investigated as high-rate lithium-storage materials due to their shortened charge-transport length and high surface area. The pseudocapacitive effect plays a considerable role in electrochemical lithium storage when the electrochemically active materials approach nanoscale dimensions, but this has received limited attention. Herein, a series of (Mg 0.2 Co 0.2 Ni 0.2 Cu 0.2 Zn 0.2 )O electrodes with different particle sizes were prepared and tested. The ultrafine (Mg 0.2 Co 0.2 Ni 0.2 Cu 0.2 Zn 0.2 )O nanofilm (3-5 nm) anodes show a remarkable rate capability, delivering high specific charge and discharge capacities of 829, 698, 602, 498 and 408 mA h g À1 at 100, 200, 500, 1000 and 2000 mA g À1 , respectively, and a dominant pseudocapacitive contribution as high as 90.2% toward lithium storage was revealed by electrochemical analysis at a high scanning rate of 1.0 mV s À1 . This work offers an approach to tune the lithium-storage properties of (Mg 0.2 Co 0.2 Ni 0.2 Cu 0.2 Zn 0.2 )O by size control and gives insights into the enhancement of pseudocapacitance-assisted lithium-storage capacity.

A low-cost porous hydrated ammonium vanadate/Zn system with a ZnSO4-based electrolyte exhibits high reversible capacity and remarkable stability.

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