The present invention belongs to the technical field of
solid-state batteries, and discloses a composite
solid electrolyte and a
solid-state battery. The composite solid
electrolyte includes a modified solid
electrolyte layer on the positive
electrode side and a modified solid electrolyte layer on the negative
electrode side that are combined together. The modified solid electrolyte layer on the positive
electrode side uses a heavy
metal ion MOF material with a large
radius to provide an additional path for
lithium ion transmission, and can also stabilize the interface and reduce the formation of voids during the interface
side reaction process. The modified solid electrolyte layer on the negative electrode side uses a
light metal MOF material to protect the
lithium metal surface, reduce the uncontrollable occurrence of side reactions, and the lower deposition potential of the
light metal also reduces the
capacity loss caused by excessive deposition of
impurity metals. The addition of MOF materials in the solid electrolyte
layers on the positive and negative electrode sides increases the
mechanical strength of the membrane, reduces the
crystallization phenomenon of long-chain polymers, and generally increases the
ionic conductivity of the solid electrolyte, while stabilizing the
reaction interface and increasing the cycle stability.