Synthesisi,Characterization And Electrochemical Properties Of Lithium Ion Battery Cathode Based On The Bimetal-Organic Frameworks

With the continuous progress of society and the rapid development of science and technology,demand for convenient electronic devices is growing,which further promotes the improvement of solid state battery technology.Lithium ion battery is of specific capacity,high efficiency and long life,and become the preferred power source in the electronic consumer market,and its the annual output reach as much as billions.It also plays an important role as ideal electrochemical storage devices in renewable energy plants and power systems for new energy vehicles such as hybrid and electric vehicles.However,to improve the performance of lithium ion battery to satisfy people’s energy storage requirements,one of the challenges is to explore suitable anode materials.At present,lithium cobalt oxide（LiCoO₂）with layered structure is widely used in the cathode materials of lithium ion batteries.In addition,other electrode materials,such as lithium manganese oxide（LiMn₂O₄）,lithium nickel oxide（LiNiO₂）,lithium iron phosphate（LiFePO₄）and ternary materials,etc are also used.These materials are mainly synthesized in solid method,leading to difference in performance between different batches of material.In order to synthesize cathode with structure stability,performance batch uniform,we used the double metal MOFs as precursors to synthesize the lithium ion battery cathode and studied their electrochemical performance.The content mainly includes the following sections:（1）Bimetallic organic complexes[Li₂Mn₃（ipa）₄（DMF）₄]_n was synthesized using by solvothermal method,and then further calcified at high temperature to prepare.Spinel type lithium manganate（LiMn₂O₄）cathode under different atmosphere with various calcination time.The determination of the electrochemical properties of the lithium manganese acid,indicated that the direct at calcination in air atmosphere under850℃for 12h was the optimal synthetic conditions.The initial discharge specific capacity is 95.7 mAh/g at0.1C,and the capacity retention rate is 89.9%after 500 cycles at high rate 1C.The preprared material exhibits high charge-discharge specific capacity and excellent electrochemical cycle performance in lithium ion batteries.（2）Similar to the above method,bimetallic organic complexes[Li₂Co（ipa）₂（EtOH）]_n was synthesized as a precursor and used to preprare the layered cobalt acid lithium cathode,at various temperature,calcination time,and synthetic steps.We found that the sample has a maximum discharge capacity of 143.8mAh/g,and also has a good cycle under high-rate circulation,what is obtaind by heating at 600℃for 12h under N₂ atomsphere,then calcination at 800℃for 4h in the air.（3）On the basis of the previous experimental preparation of lithium manganate,we synthesize bimetallic organic complexes[LiMn（HCO₂）₃]_n materials with small molecular structure as the precursor,and further calcinations were performed at different temperature,and time to prepare the rich lithium manganese Li₂MnO₃-LiMn₂O₄,as active material of lithium ion battery cathode,Electrochemical performance showed in air at 850℃for 12h,has the first charge and discharge of the sample,obtained was153.9 mAh/g,exhibiting high charge-discharge ratio capacity and good rate cycling performance in lithium-ion batteries.