Design,Synthesis And Lithium Storage Or Photocatalytic Properties Research Of Transition Metal Oxide Composites

Nowadays,the growing environmental pollution has brought great challenges to the development of economy and society,and human's modern life.Environmental protection and sustainable development become the priority must be considered.The policies for environment governance are prevention and treatment,for example,reducing the use of fossil fuels,increasing the efficiency of sewage treatment,and so on.Therefore,the developmet of green renewable energy and the new technology for sewage treatment are the focus of current research.Lithium ion batteries,as a kind of renewable clean energy,have the characteristics of environment-friendly,high energy,portability,are widely used in the digital products,military equipment,medical equipment,electric vehicles,smart grid,and other fields.With the development of science and technology,people put forward higher requirements on the performance of lithium ion batteries.The realization of high performance lithium ion batteries depends on the electrode materials of the structure design and the improvement of performance.In many alternative materials,transition metal oxide materials have the advantages of high specific capacity,high power density,rich resources,can satisfy the requirement of higher performance for lithium ion batteries.Photocatalytic technology,as a kind of advanced green technology,use the absorption of photocatalys to the photon energy under the light,which make harsh conditions of reaction in a mild environment can be.In recent years,transition metal oxide materials,as a kind of semiconductor photocatalysts,get rapid development in the field of pollution control application.However,photocatalysis technology,as a kind of new technology,still has main drawbacks of the relatively low adsorptive performance and the easy recombination of photoexcited carriers in semiconductor photocatalysts.In this paper,we put forward corresponding improving methods aimed at existing problems in the different research field.The researches were carried out from the following several aspects:?1?For the problem of the poor capacity retention caused by the large volume changes of ?-MnO₂ as an anode for lithium ion batteries during discharge/charge processes.We design hierarchical ?-MnO₂@SnO₂ heterostructures materials,and study the electrochemical performance of heterostructures.Experiments showed thatthe ?-MnO₂@SnO₂ heterostructures showed obviously improved electrochemical performance in terms of initial discharge capacity?1548 m Ah g-1at 100 mA g-1rate?,and capacity retention?437 mAh g-1 at 50 th cycle at 100 mA g-1 rate?compared to both single components.?2?For the problem of the capacity fade caused by the dissolution of Mn of LiMn₂O₄ as a cathode for lithium ion batteries during discharge/charge processes.We design the TiO₂-coated LiMn₂O₄ nanorods materials,and study the electrochemical performance of nanocompasities.The electrochemical performance tests showed that TiO₂-coated LiMn₂O₄ nanorods materials exhibited a capacity retention ratio of 95.5%at a rate of 0.1 C in 100 cycles,which is better than that of pristine LiMn₂O₄?81.4%?.?3?For the problem of the relatively low adsorptive performance and the easy recombination of photoexcited carriers of ZnO photocatalyst.We design the ZnO/rGO/PANI ternary nanocomposite,and study the photoelectrochemical performance and the photocatalytic performance.The ZnO/rGO?7 wt.%?/PANI?10wt.%?photocatalyst showed an enhanced photocatalytic performance for the photodegradation of methyl orange with a maximum degradation efficiency of 99%within 60 min under UV light irradiation compared to pure ZnO?15%?.