The Preparation Of Micro/nano-structural Transition Metal Oxides By Template Method For Anode Materials Of Lithium-ion Batteries

With the continuous deterioration of energy and environment problems,society urges the secondary and clean energy to deal with this embarrassment,which cause the increasing research interests of batteries.It is reported that nano-sized transition metal oxides could be the potential anode materials for lithium-ion batteries in 2000s.But the huge volume change and poor electroconductivity lead the decline of performance.Herein,micro/nano-structural transition metal oxides have been prepared via template method in this work.By means of the control of morphology and porosity,these materials combine the features of nanoparticles and microframe,which exhibit the excellent performance for anode materials of lithium-ion batteries.The main contents are as follows:1.We report the synthesis of porous hollow Co₃O₄ microspheres consisting of nanoparticles with controllable porosity via spray pyrolysis.The size of the nanoparticles and the porosity of microspheres can be controlled by the amount of the gaseous template used,in this case urea.According to the characterization of morphology,the porosity of Co₃O₄ microspheres highly relate to the concentration of urea.The test of batteries shows that porosity directly influences the electrochemical performance of materials.The optimized material displays satisfactory rate ability of 881.3 mAh/g at 1780 mA/g after300 cycles.2.We develop a general strategy,the gelatin-assisted hydrothermal-calcination process,to prepare hierarchical porous transition metal oxides and their composites,including Fe₂O₃,Mn₂O₃,Co₃O₄,ZnCo₂O₄,MnCo₂O₄ and?Co,Mn?₃O₄ In addition,the porosity could be tunable by the different calcining temperature.Typically,step-like hierarchical porous Fe₂O₃ prepared at 500?delivers the outstanding performance of 1301.7 mAh/g after 600 cycles and 888.8 mAh/g after 500 cycles at 1000mA/g for lithium-ion storage.In addition,ZnCo₂O₄ electrode material also shows the specific capacity of 1005.8 mAh/g at 500 mA/g after 180 cycles.Finally,Na_0.7MnO₂ cathode material prepared from MnCO₃ also displays the 140.9 mAh/g over 50 cycles at 40 mA/g for sodium-ion storage.