| High-temperature lithium battery,the development of thermal battery technology,aims to solve the problem of high-temperature energy supply for oil,natural gas and geothermal explo-ration.At present,the development of lithium alloy anode materials and low-melting nitrate electrolyte materials is relatively mature,so it has become an effective way to seek matched cathode materials to improve the voltage,specific capacity and high-temperature stability of high-temperature lithium batteries.Metal Organic Frameworks?MOFs?,with excellent thermal stability,abundant pores and large specific surface area,and their derivatives have been used as electrode materials in lithium ion batteries,and are expected to be high-performance high-temperature lithium battery cathode materials.This work applied MOFs into high-temperature lithium batteries,using MOFs as precursors to develop two manganese oxide cathode materials with large specific surface area and porous structure.Then the discharge performance of them was studied.?1?The Mn-BTC precursor has been synthesized by self-assembly at room temperature,and the effects of raw materials ration and the quantity of dispersant PVP on morphology and structure were studied.The results indicated that when the molar ratio of Mn?CH3COO?2·4H2O and H3BTC is 1.5:3,the masses are 0.98 g and 1.681 g,respectively,and the amount of PVP is 2 g,flower-shaped microspheres with uniform dispersion and even particle size can be ob-tained.After roasting and lithium treatments,the porous Li Mn2O4microsphere was prepared and applied into Li-Mg-B/Li NO3-KNO3/Li Mn2O4 high temperature lithium battery.The DSC test exhibited that Li Mn2O4 cathode material have good thermal stability in the temperature range from room temperature to 300?.Under the conditions of 200?and 10 m A·cm-2 current density,the specific capacity of Li Mn2O4 cathode reached 258.89 m Ah·g-1.These results can provide useful information for the application of MOFs-derived metal oxides in high-tempera-ture lithium batteries.?2?The Mn3O4 cathode material has been successfully prepared by high-temperature treat-ment of the precursor of Mn-BTC.The results of SEM and BET tests showed that the prepared Mn3O4 basically maintained the porous microsphere of the precursor,and its specific surface area reached 23.9043 m2·g-1.The thermal stability of Mn3O4 and its chemical compatibility with nitrate electrolyte and graphite were investigated by DSC measurement.It indicated that Mn3O4 cathode material satisfied the requirements of working in the temperature range of 150?300?.The results of discharge test stated that temperature and current density had a great influence on the discharge performance of Li-Mg-B/Li NO3-KNO3/Mn3O4 batteries.The spe-cific capacity of Mn3O4cathode material reached 545.73 m Ah·g-1 at 300?and 10 m A·cm-2discharge condition.The large surface area and hierarchical pore structure of Mn-BTC-derived Mn3O4 will be instrumental in improving the conductivity of ions and electrons,increasing the specific capacity of the material. |
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