High-conductivity solid electrolyte prepared by sol-gel method

Abstract

The invention relates to the technical field of solid electrolyte, and in particular, relates to a high-conductivity solid electrolyte prepared by a sol-gel method. Any one or a composition of more oflithium nitrate, germanium oxide and tetraethoxysilane is used as a doping agent, lithium titanium aluminum phosphate is used as a main material, the doping agent is embedded into the lithium titanium aluminum phosphate framework by the sol-gel method, and an NASICON structure is formed; the solid electrolyte disclosed by the invention is small in grain boundary impedance, high in ionic conductivity, low in sensitivity to heat treatment temperature and suitable for industrial production, and integrates the characteristics of low synthesis temperature, low energy consumption, high product purity, small particle size and high density of traditional sol-gel; citric acid and ethylene glycol are adopted as auxiliary agents, environmental pollution is prevented, the temperature and the stirringrate are reasonably controlled, and the cost is reduced.

Description

technical field [0001] The invention relates to the technical field of solid electrolytes, in particular to a high-conductivity solid electrolyte prepared by a sol-gel method. Background technique [0002] With the development of industrial society, the increase in energy consumption and the depletion of non-renewable resources, people's demand for new energy is becoming more and more urgent, and the requirements for energy storage technology are becoming more and more stringent. Lithium-ion batteries are considered to have very broad development prospects in energy storage due to their high energy density and long service life. [0003] At present, commercial lithium-ion batteries use organic electrolytes. Because they are flammable and easy to leak, there are great safety hazards in large-scale use. In addition, the existence of electrolytes makes the battery structure complicated, making it difficult to miniaturize the battery. develop. Solid-state batteries have high t...

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Problems solved by technology

[0004] In the prior art, oxide solid electrolytes are mainly prepared by co-precipitation method, sol-gel method, solvent method, microwave synthesis method, electrospinning method, high-temperature solid-phase method, etc., such as patent No. CN201810697845.9 discloses a A novel lithium ion conductive oxide solid electrolyte and a preparation method thereof, specifically weighing raw materials according to a designed stoichiometric ratio and performing wet ball milling and mixing; calcining the mixed raw materials step by step to obtain a solid electrolyte powder; The electrolyte powder is kept under a suitable pressure for 30-60 minutes, and then the green body is buried in the powder of the same composition, and the temperature is raised to 1100-1200°C at 1°C / min-2°C / min, and kept for 12h-24h , to prepare the required solid electrolyte, but the calcination temperature is too high, the energy consumption is high, and the impurities are difficult to recycle due to direct calcination; CN201710962086.X discloses a lithium halide-doped oxide solid electrolyte and its low-temperature sintering method , specifically a perovskite-type, NASICON-type, garnet-type electrolyte as a matrix, using a lithium halide solution and a composite of an oxide solid electrolyte, and sintering at a low temperature into a solid electrolyte; the preparation method is mainly LATP , LLTO, LLZO solid electrolyte ball milling or self-made cubic phase lithium lanthanum zirconium oxygen solid electrolyte powder ball milling sintering to obtain cubic phase LLZO solid electrolyte powder, LiX solution is added to the above solid electrolyte powder, pressed into a sheet or coated into a film, placed Sintering in a muffle furnace at a low temperature of 100-250°C for 1-10 hours, the selection of raw materials is strict, the cost of raw materials is high and it is not easy to obtain; at present, most of the existing medium oxide solid electrolytes stay in the laboratory stage, and the preparation method consumes a lot of energy, It takes a long time, and the conductivity has a large dependence on the heat treatment temperature

In addition, based on the consideration of industrialization factors, coprecipitation method, sol-gel method and high-temperature solid-phase method are more suitable for large-scale synthesis, but the prepared solid electrolyte has high grain boundary resistance, low ionic conductivity, and is sensitive to heat treatment temperature.

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