Morphology-controlled Synthesis And Electrochemical Performance Of Nano/Micro Structure Metal Oxide Materials

With the rapid development of new energy materials, high performance of lithium ion battery has received the attention of the researchers. Ni, Sn-base metal oxide materials with low price, wide source, and high theoretical specific capacities of 718 mAh/g and 782 mAh/g, have gained wider attention as promising anode materials for new lithium-ion battery. However, Ni, Sn-base metal oxide materials also have poor cycling performance and specific capacity. In the present work, we propose new strategies to design and synthesize nano/micro structure NiO@C, NiFe2O4 and SnO2@TiO2 lithium-ion battery cathode materials, by using MOFs as templates, building mixed matrix and microwave HCI erosion method, respectively. The effects of the different reaction conditions on the morphology and electrochemical performance of the synthesized materials were investigated in deeply.Hollow NiO@C microspheres core-shell structure anode materials from metal-organic frameworks are synthesized through solvothermal method. The specific surface area is 182.646 m2/g, has a fluffy mesoporous structure. The mesoporous structure can provide sufficient reaction space and transmission path of lithium ions in the process of electrochemical reaction, therefore, improve the electrochemical properties of materials. By electrochemical performance test, it shows that under the constant current density of 1C, after 200 times charging and discharging cycle, the discharge capacity of the material remains at 962 mAh/g. That exhibit excellent electrochemical properties. With simple operation, low price, the approach may shed light on a new avenuefor the fast synthesis of hollow core-shell structure materials for energy storage, sensor, catalyst and other new applications.The MOFs as the template, combined the advantages of mixed matrix and hollow nanocubic structure, synthesize a hollow mesoporous structure NiFe2O4 nanocubic anode material by using solvothermal method. The hollow nanocubic structure can shorten the lithium ion diffusion path, and provide enough space. The mechanical stress induced by the volume changes during cycling can be fully mitigated. In addition, hybrid element can make the volume change step by step in the process of electrochemical cycling. Furthermore, its capacity can maintain at 975 mAh/g, when the current density of 1C, after 200 times of electrochemical cycle. Then, the capacity of the material can be reached 652 mAh/g, when a constant current density of 10C. The test shows excellent electrochemical performance of materials. Moreover, the approach may shed light on a new avenue for the fast synthesis of hollow nanocubic functional materials for energy storage, environmental optimization and other new applications.The a-Fe2O3 as template, a novel synthesis containing microwave-assisted HC1 etching reaction and precipitating reaction is employed to prepare hierarchical hollow SnO2@TiO2 nanocapsules for anode materials for Li-ion batteries. In particular, the coatingof TiO2 onto SnO2 can enhance the electronic conductivity of hollow SnO2 electrode. As a result, we can find the material has an excellent electrochemical performance. The SnO2@TiO2 nanocapsule electrode exhibits a stable capacity of 770 mAh/g at 1C, and after 200 times of electrochemical cycle, the capacity retention can keep over 96.1%.This approach may shed light on a new avenue for the fast synthesis of hollow nanocapsule functional materials for energy storage, catalyst and other new applications.