Modification And Low Temperature Electrochemical Properties Of Zinc Manganate Anode Materials

Spinel zinc manganate?ZnMn₂O₄?is the most promising anode material due to its abundant reserves,friendly environment,low working potential and high energy density.However,ZnMn₂O₄ has the disadvantages of low conductivity,large volume change and large capacity attenuation in the first discharge process,which limits its development.In this paper,the main synthesis method of ZnMn₂O₄ was optimized and the composite modification of ZnMn₂O₄ was carried out.We prepared ZnMn₂O₄ with different morphologies through coprecipitation,mixed solvent heating and microemulsion method.We used different transition metal oxides combined with ZnMn₂O₄ to improve composite materials'electrochemical properties by the synergistic effect of the two materials.In addition,we also studied the low temperature?-15??performance of ZnMn₂O₄.The specific research has been summarized as follows:?1?ZnMn₂O₄ was prepared by the combination of co-precipitation and high-temperature calcining.The influences of different calcining temperatures on the morphology and electrochemical properties of the materials were studied.The optimal calcining temperature was selected for further study.ZnMn₂O₄/SnO₂ composite was prepared by ultrasonic method.The influence of SnO₂ addition on the morphology and electrochemical properties of composite anode materials was investigated.The electrochemical test results showed that add SnO₂ can improve the electrochemical properties of composite materials.For convenience mark the following ZnMn2O4 abbreviated as ZMO.When the addition amount of SnO₂ is 10%,the electrochemical properties of the composite material are the best,especially when the average discharge specific capacity of ZMO-SnO₂?10%?can still be maintained at 563 mAh·g^-1 from the high current density of 1000 mA/g to the low current density of 100 mA/g,showing excellent magnification performance.?2?ZnMn₂O₄ with microspherical structure was prepared by mixed solvent thermal method.When urea was used as precipitant,the specific discharge capacity was 1295 mAh·g^-1for the first cycle.ZMO/CuO and ZMO/Co₃O₄ composite electrode materials were also synthesized by solvent heat method.The results show that the addition of CuO and Co₃O₄ can increase the initial specific capacity of the composite electrode material.The initial discharge specific capacity of ZMO/CuO composite material is 1352 mAh·g^-1,which can maintain 890mAh·g^-1 after 50 cycles under the current density of 100 mA/g.?3?studies on low temperature performance of zinc manganate:?1?based on the modification of the electrolyte,we prepared ZnMn₂O₄ by microemulsion method.The influence of electrolyte composition on low temperature performance of lithium ion battery was studied.Results showed that the quaternary electrolytic fluid system can improve the low temperature electrochemical performance of lithium ion batteries;?2?Modification of electrode materials:ZMO/Fe₃O₄ and ZMO/Ag composites were prepared by co-precipitation method.ZMO/Ag showed the best performance at low temperature and the initial discharge specific capacity was1022 mAh·g^-1,when returned to a low current of 100 mA/g after 70 times of circulation,the average discharge specific capacity was 332 mAh·g^-1(while the average discharge specific capacity of znic maganate was 167 mAh·g^-1),The addition of Ag greatly improved the low temperature electrochemical properties of composite anode materials.