Lithium lanthanum bismuthate-based solid electrolyte material and preparation method thereof

Abstract

The present invention discloses Lithium lanthanum bismuthate-based solid electrolyte material and preparation method thereof. The chemical formula of the material of Lithium lanthanum bismuthate-based solid electrolyte after the doping of lanthanum and the doping of lithium are conducted is La(3-x)AxLi(5+delta)Bi(2-y)ByO12. In the formula, A is the lanthanum position dopant, X is a value from 0 to 1.25, B is the bismuth position dopant, and Y is a value from 0 to 1.25. The preparation method of the material is as follows: according to the formula, weighing nitrates or carbonates or chlorides or acetates or alkoxides or oxides soluble in acids of lithium, lanthanum, bismuth, the lanthanum-position dopant and / or the bismuth-position dopant, preparing a solution by using the above chemicals,adding a lanthanum salt solution, a bismuth solution, a solution of lanthanum-position dopant and / or a solution of bismuth-position dopant dropwisely, adding citric acid and nitric acid successively to obtain a sol, adding a water-soluble polymer into the sol to form a gel, drying the gel, performing heat treatment to obtain nanocrystal powder, moulding the powder into a green body, and calciningto obtain the Lithium lanthanum bismuthate-based solid electrolyte material. The prepared material can be used as a solid electrolyte material and can be applied to all-solid-lithium ion battery.

Description

technical field [0001] The invention relates to a solid electrolyte material and a preparation method, in particular to a lanthanum bismuth lithium-based solid electrolyte material and a preparation method thereof. Background technique [0002] All-solid-state lithium-ion battery is a new generation of lithium-ion battery recently developed. Compared with the current commercial lithium battery, it has the advantages of easy miniaturization, good safety performance, easy processing, and no battery internal pressure. It can effectively eliminate the traditional Liquid electrolyte lithium-ion batteries have safety problems such as flammability, volatility, electrolyte leakage, and poor heat resistance, and it is expected to use metal lithium as the negative electrode to greatly increase the specific capacity of the battery. Therefore, all-solid-state lithium-ion batteries are expected to have broad application prospects in fields requiring high safety such as microelectronic de...

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Problems solved by technology

This lanthanum lithium titanate with perovskite structure and lithium inorganic solid electrolyte materials with similar structures have disadvantages. First, although the bulk conductivity at 25°C is 10 -3 S / cm, which can be compared with the currently practical polymer liquid electrolyte, but its grain boundary resistance is as high as 50 times the bulk resistance, resulting in a total conductivity of only 10 at room temperature. -5 S / cm scale; Secondly, the electrochemical stability is poor, when it is in direct contact with metal lithium, the two will undergo redox reaction, resulting in Ti 4+ reduced to Ti 3+ , resulting in a higher electronic conductivity, so it is not suitable as an electrolyte in an all-solid-state lithium-ion battery; again, the synthesis temperature for its preparation is too high, reaching 1300 ° C, such a high synthesis temperature has caused a large loss of lithium oxide , and makes the composition of titanium, lanthanum and lithium difficult to control

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