Research On The Preparation And Performanc Of A New Type Fluorophosphate All-Solid-state Sodium-ion Electrolyte Study

Electric transportation is developed increasingly following by the energy shortage problem increasingly serious. The application of lithium-ion battery has been approaching maturity for human at present, however, its low-cost raw material lead sodium-ion batteries to become a rising star. Sodium-ion electrolytes as a core part of the sodium-ion batteries have become the research hot spot. Sodium-ion electrolytes are the important part of sodium-ion batteries, the current can be applied at room temperature solid-state sodium-ion battery electrolyte highest conductivity has reached 3×10-4 S·cm-1. However, the high conductivity of the electrolyte is mainly to chalcogenide glass ceramic materials, and the cost of chalcogenide compounds high, chemically unstable and hard to be produced. Therefore, it is widespread application of solid-state batteries by looking for a new type all-solid-state sodium-ion electrolyte, which is low cost, high ionic conductivity, chemical stability, and simple synthetic process.This paper discusses the high temperature melting experiments and manufactured a new solid-state fluorophosphates glass, and then use the second-heat treatment method to control the crystallization process of glass matrix is formed with fast ion conductor structure of microcrystalline glass electrolyte materials, systematic research on the material of theoretical basis, preparation process and the performance of electrolyte materials. The specific content is as follows:1. Briefly introduces the development background of all-solid-state battery, summarizes the basic knowledge of all solid sodium ion batteries, focusing on the application of solid electrolyte in sodium sodium-ion in the cell and its advantages and disadvantages. Finally, the research contents of this thesis and research mechanism. 2. Summarizes the all-solid-state fluorophosphates glass, glass ceramics and crystal electrolyte manufacturing method, detailed introduces the structural testing of electrolyte materials, microstructure test, electrochemical performance test, chemical properties and thermal stability of test steps. 3. Detailedly introduce the mechanism which is used to choose the glass and the glass-ceramic system of the Na₂O-B₂O₃-P₂O₅-ZrO₂（NBPZ） and the（Na2O+Na F）-Ti O2-B₂O₃-P₂O₅-Zr F₄（NTBPZ）. 4. An oxide all-solid-state sodium-ion electrolyte is prepared by the second-heat treatment method that can be controlled crystallization, the basic glass system of the electrolyte is Na₂O-B₂O₃-P₂O₅-ZrO₂（NBPZ）. In order to improve the performance of the electrolyte, the devitrification of the NBPZ glass is by controlling the second-heat treatment temperature and time.The sodium-ion conductivity is up to 10-5 S·cm-1 at room temperature. 5. A modified all-solid-state fluorophosphate sodium-ion electrolyte is prepared by the second-heat treatment method which can be controlled crystallization, the basic glass system of the electrolyte is（Na2O+Na F）-Ti O2-B₂O₃-P₂O₅-Zr F₄（NTBPZ）. By controlling the second-heat treatment temperature and time to control the material crystal size, density and uniformity devitrified by the NTBPZ glass, in order to improve the material electrical properties, chemical properties and thermodynamic stability. Finally obtain a novel all-solid-state fluorophosphates sodium-ion electrolyte material, the activation energy is 13.9 k J·mol-1, sodium-ion conductivity is up to 3×10-5 S·cm-1 at room temperature and high temperature resistance below 500 °C in air atmosphere without chemical reaction.