Composite solid electrolyte for secondary battery, secondary battery including same, and method for preparing same

Disclosed are a composite solid electrolyte for a secondary battery including a negative electrode, and a method for preparing the same, in which the composite solid electrolyte contains a first solid electrolyte including a compound represented by Formula 1, and a second solid electrolyte including a compound represented by Formula 2, and wherein the first solid electrolyte is disposed adjacent to the negative electrode. Lt; formula 1gt; li < 1 + x + 2y > Al < x > Mg < y > M < 12-x-y > (PO4) < 3 lt >; formula 2gt; li1 + x + 2yAlxMgyM22-x-y (PO4) 3 in formulae 1 and 2, M1, M2, x and y are as defined in the detailed description. 公开了用于包括负极的二次电池的复合固体电解质、以及其制备方法，其中所述复合固体电解质含有包括由式1表示的化合物的第一固体电解质、和包括由式2表示的化合物的第二固体电解质，和其中所述第一固体电解质邻近于所述负极设置。Li1+x+2yAlxMgyM12-x-y(PO4)3Li1+x+2yAlxMgyM22-x-y(PO4)3在式1和2中，M1、M2、x和y如详述的说明书中所定义。