Study On Preparation And Electrochemical Performance Of LiV₃O₈ Nanorods As Cathode Materials For High Power Andlong-life Rechargeable Lithium-ion Batteries

Lithium-ion batteries(LIBs) have revolutionized diverse portable consumer electronic devices over the past two decades. However, the next market opportunities will be much tougher for current state-of-art LIBs to conquer, as the emerging applications(such as hybrid electric vehicles(HEVs), electrical vehicles(EV)) mostly require high energy and power density with long cycle life. Therefore, electrode materials possessing high reversible Li storage capacity and rapid solid-state lithium-ion and electron transport are indispensable to meet the increasing needs of energy storage.Monoclinic lithium trivanadate(Li V3O8) has been widely studied as cathode materials for LIBs due to its good features, such as high specific capacity, good structural stability, low cost and desirable safety. However, there also exist some stumbling blocks restricting further application of Li V3O8 materials, like low electronic conductivity and slow rate of lithium-ion diffusion, which are unfavourable for rate performance(especially at high-rate).In the present work, we demonstrate a two-step route for synthesizing Li V3O8 nanorods with a confined preferential orientation by using self-made VO2(B) nanosheets as precursor. In comparison with bulk Li V3O8 materials fabricated by commercial VO2 precursor, the special structures of nanorods endue Li V3O8 with markedly enhanced reversible capacities, high-rate capability and long-term cycling stability as cathodes for lithium storage. Li V3O8 nanorods electrode can deliver a desirable reversible capacity of 200 m A h g-1 at a moderately high rate of 600 m A g-1 with high capacity retention of 95% after 100 cycles. More impressively, appreciable initial capacities of 161 and 158 m A h g-1 can be achieved for the Li V3O8 nanorods at extremely high rate of 2000 and 3000 m A g-1, with minimal capacity loss of 0.037% and 0.031% per cycle throughout 300 and 500 cycles, respectively.The energetically optimized electron conduction and lithium diffusion kinetics in electrode process may shed light on the superior electrochemical properties of the Li V3O8 nanorods, which primarily benefit from the nanoscale grain size, large specific surface area and restricted preferential ordering along(100) plane. Therefore, it is anticipated that such Li V3O8 nanorods are highly promising as candidate cathode materials for high power and long lifespan rechargeable lithium batteries.Moreover, we have given an preliminary exploration and attempt on the capacity for sodium storage of the as-prepared VO2(B) nanosheets, showing promising potential application in sodium-ion batteries.