The invention relates to a preparation method of a
lanthanum-doped
lithium borate coated LATP
solid electrolyte, which comprises the following steps: S1, mixing a
lithium source, an aluminum source, a
lanthanum source, a
titanium source and a
phosphorus source, putting the mixed material into a dispersing agent, putting into a constant-temperature water bath stirrer, and heating and stirring until the mixture is completely dried to obtain a mixed
raw material; s2, performing high-temperature primary
sintering on the mixed
raw material in an
air atmosphere to obtain a
composite oxide; s3, performing crushing treatment on a
composite oxide, adding
lithium borate, and performing uniform mixing to obtain a mixture; the
mass ratio of the lithium-containing compound to the
composite oxide is (0.01-0.05): 1; and S4, tabletting the mixture, and carrying out high-temperature secondary
sintering in an
air atmosphere to obtain the finished product lithium
titanium aluminum phosphate material. The problems that in an existing scheme, the final
calcination temperature of a
solid electrolyte is generally up to 1100 DEG C or above,
high energy consumption is likely to be caused, meanwhile, Li loss is caused, non-conductive AlPO4 is introduced, the
crystal structure is unstable, the
powder sintering performance is poor, and the
ionic conductivity is reduced are solved.