The Liquid Phase Deposition And Electrochemical Properties Of Vanadium-based Compound Films

Due to the limited reserves of non-renewable resources and environmental pollution caused by the use process,the novel clean energy resource and energy storage equipment have been extensively explored.Lithium ion battery is one of the most widely used energy storage devices.At present,vanadium compounds have been used as electrode materials for lithium batteries due to its abundant resource and the variable valence states.In order to further simplify the preparation process of the vanadium compounds electrode materials and improve its electrochemical performance,a new,facile low temperature liquid phase deposition method has been employed to deposit vanadium compounds followed by an annealing process.Furthermore,the synthesis condition was explored and optimized.The main research results are as follow:?1?VOSO₄,oxalic acid and NaOH were used to synthesize the NaV₆O₁₅5 thin films through a novel low temperature liquid deposition followed with an annealing process.The influences of the deposition parameters and annealing temperature were investigated in detail.The product NaV₆O₁₅ films were obtained by annealing the as-deposited films.With the increase of the annealing temperature,the morphology and composition of NaV₆O₁₅films changed.The as-deposited films were composed of hydrated vanadate with the morphology of flake-like crystal clusters.While the products annealed at 500?were composed of the monoclinic crystal NaV₆O₁₅ with a morphology of nanorods.The products annealed at 500?exhibited better electrochemical properties than that of the products annealed at 300?and 400?.The Capacity attenuation of the products NaV₆O₁₅may be related to the irreversible structure evolution and decreased adhesion to the substrates of the product.?2?V₂O₅ thin films were prepared by a novel low temperature liquid deposition using VOSO₄,oxalic acid and ammonia as raw materials.The influences of the deposition parameters and annealing temperature on the preparation of the V₂O₅ thin films were investigated.After annealed at 300?,400?and 500?,the V₂O₅ thin films were completely formed.But the morphology of the products annealed at different temperatures were different.The product annealed at 400?with a morphology of layered-like nanorods exhibited better electrochemical properties than that of the products annealed at500?and 300?.?3?K_0.23V₂O₅ thin film was prepared by low temperature liquid deposition with VOSO₄,oxalic acid and KOH as raw materials.The influences of the deposition system's pH and raw material ratio on the deposition process were explored.K_0.23V₂O₅ films were obtained by calcination at 400?.The product K_0.23V₂O₅ film was composed of nanorods,which had good rate performance and cycle performance.The decrease of the capacity during the cycles was mainly caused by the decrease of the adhesion between the film and the substrate.