Anionic defect-enriched ZnMn2O4 nanorods with boosting pseudocapacitance for high-efficient and durable Li/Na storage

Abstract

Anionic defect (oxygen vacancies)-enriched ZnMn2O4 nanorods (OZMO) were manufactured through a facile coprecipitation/chemical reduction route. The synergetic mechanism of rich oxygen vacancies, abundant mesopores, and prominent pseudocapacitance endows the OZMO nanorods with long-term chemical durability for high-efficient lithium/sodium storage. When evaluated as anodes for lithium-ion batteries, the OZMO electrode exhibits a conspicuous reversible capacity of 1566.7 mAh g−1 after 50 cycles at 0.1 A g−1, remarkable cyclability with 380.1 mAh g−1 after 1000 cycles at an ultrahigh current density of 10 A g−1, as well as a good environmental adaptation with 568.6 and 811.4 mAh g−1 at −5 °C and 55 °C. For sodium-ion batteries, the OZMO electrode delivers a stable discharge capacity of 110.8 mAh g−1 after 1000 cycles at a large current density of 1 A g−1. The UV–Vis diffusive reflectance spectrum shows that the OZMO sample has a narrow bandgap, thus improving the electrical conductivity. Moreover, this strategy may increase the active sites, which provides a large electrolyte/electrode contact area and shortens the diffusion distance for both ions and electrons, thereby buffering the volume variation originated from the repeated Li+/Na+ intercalation/deintercalation process.