Preparation Of ZnFe₂O₄ And The Electrochemical Performance

With the development of science and technology,the popularization of smart life and environmental protection concepts,renewable energy plays an important role in the social process.Lithium-ion batteries stand out among a lot of renewable energy sources with many advantages such as high efficiency,environmental protection,and economy.The increasingly high requirements for battery of people have promoted the development and improvement of lithium ion batteries.Electrode materials,as the most critical components of lithium ion batteries,have also received extensive attention and research.As a negative electrode material,zinc ferrite has a wide range of sources,low pollution,and low cost.And the theoretical capacity is three times that of the traditional negative electrode material graphite.It is an alternative negative electrode material that meets the current battery development.However,zinc ferrite will have serious volume changes and rapid capacity decay during charging and discharging cause of the material's own characteristics,which limit its further development.Based on this,this article has prepared and modified zinc ferrite materials.The specific work is as follows:1. Using a mixed solution of deionized water and ethylene glycol as a solvent,and urea as a coprecipitating,we designed a group of conditional experiments with the simple solvothermal/hydrothermal method agent to prepare a pure phase nano-ZnFe₂O₄.TEM shows that the materials are aggregated from small nanospheres to large nanospheres.SEM shows that the large nanospheres are aggregated into different shapes with rough surfaces and many voids.BET shows that the specific surface area of the material is 55.9 m² g^-1.The material and the lithium sheet were assembled into a button battery,and the results of the study show that:the initial discharge capacity is1267 mAh g^-1 in the 0.1-3.0 V voltage range and 0.5 A g^-1 current density,and the capacity decayed quickly in the first 30 charge,then the capacity gradually increased.The discharge specific capacity of the material remained at 741 mAh g^-1 and 908 mAh g^-1 at 150 and 400 cycles,respectively.2. Using a mixed solution of deionized water and ethylene glycol as a solvent,and urea as a coprecipitating,we designed a group of orthogonal experiments with the simple solvothermal/hydrothermal method agent to prepare the different Ni-doped ZnFe₂O₄ materials,and three representative samples were selected to research.Y01 is a nanosheet composed of particles with a particle size of less than 10 nm,Y02 is a nanorod composed of particles with a particle size of about 10 nm,and Y03 is a nanosphere with a particle size of 20 to 80 nm.Assemble the sample and the lithium chip to form a button cell.The research results show that:the initial discharge specific capacities of the three samples are 1389 mAh g^-1,1268 mAh g^-1 and 1309 mAh g^-1,respectively,in the voltage range of 0.1-3.0 V and the current density of 0.5 A g^-1.And the discharge specific capacities of the three samples were 921 mAh g^-1,449 mAh g^-1and 768 mAh g^-1,respectively,after 550 cycles.The capacity reaches 1021 mAh g^-1when Y02 is at 129 laps.After 100 cycles at a current density of 0.5 A g^-1,the rate performance test was continued at 0.1,0.2,0.4,0.6,0.8 and 1.0 A g^-1,and the specific discharge capacity of Y03 was 647,631,566,539,522 and 514 mAh g^-1.