Preparation And Electrochemical Properties Of Transition Metal Complex Lithium/Sodium Ion Battery Anode Materials

These decades witness that there is a sharply progressing necessity of energy,for the developing economy and technology.Therefore,traditional fossil recourse is increasingly consuming on a day basis,and it seems that it is going to be exhausted sooner or later.In order to solve such upcoming energy crisis,renewable energies have to develop urgently,such as solar energy,wind energy,tidal energy and the likes.To put it in another way,this reveals that the green energy demands a better energy storage and conversion equipment,and lithium-ion batteries is an adequate strategy.However,lithium ion battery capacity,utilizing graphite as anode materials,is unable to satisfy modern needs.Likewise,reserves of lithium resources is limited and fast consumption,and leading to rising prices and higher production costs.Therefore,lithium performance improvement,and the diversification of battery materials become the important answers of the problem.In fact,sodium has the characteristics of abundant,economic,environmental friendly,is expected to replace lithium-ion batteries as energy storage in a large power station.Both sodium ion battery and lithium ion batteries are supposed to improve the electrochemical properties.Transition metal complexes,with high initial capacity,good electrochemical performance and low cost,are supposed to be an ideal electrode anode materials.In this thesis,transition metal oxide or selenide with distinctive morphologies and structure is obtained electively,and performances of Sodium and Lithium battery are optimized as well.Precisely,Cu/Fe composite oxide,Mn/Fe composite oxide,and FeSe₂ composite are prepared by serious parameter,which are featured a hollow,porous cube frame structure.After that,these composites are valued by electrochemical test,combining with XRD,SEM,and TEM evaluation.The results for these tests are outlined below.Initially,the outstanding Cu/Fe composite oxide is manufactured by annealing temperature 750℃,and assembled into Lithium battery with first discharge capacity of 1251mAhg^-1.In addition,capacity of this battery holds 1024mAhg^-1 for 30 cycles,with a capacity retention of 81.85%.Secondly,Lithium battery of Mn/Fe composite oxide negative electrode demonstrates an extraordinary first discharge capacity of 1276mAhg^-1 under condition of 600℃ heating.After 30 cycles,its capacity remains 1100mAhg^-1,whose retention reaches 86.21%.Lastly,with thermal treatment of 450℃,FeSe₂ composite is fabricated and packed into Sodium battery,followed an electrochemical test with 538mAhg^-1 originally.Also,capacity of this battery,in particular,soars to 600mAhg^-1 enduring 30 cycles,due to enforced Sodium preservation.Likewise,ever after 100 cycles of 1A current density,there is a merely slide on capacity,which is 585mAhg^-1.By and large,Cu/Fe composite oxide,Mn/Fe composite oxide,and FeSe₂ composite are prepared and indicated a superior,endurable capacity with.On the top of that,this research not only contribute to elevation of capacity,but also provides an extra option for battery practice.