The invention discloses a
fast ion conductor composite material and a preparation method thereof, a secondary battery and an electric device, and relates to the field of batteries. The
fast ion conductor composite material comprises an inner core, the material of the inner core comprises
graphite and a
coating composite layer, the
coating composite layer at least partially coats the inner core, the
coating composite layer comprises a first functional layer and a second functional layer, and the first functional layer and the second functional layer sequentially extend outwards from the surface of the inner core. The material of the first functional layer comprises a
porous oxide, an MOF material and a
lithium salt mixture, the material of the second functional layer comprises
amorphous carbon, the
lithium salt mixture comprises at least two
lithium salts, the lithium salt mixture comprises a lithium-aluminum
oxide and a lithium-
cobalt oxide, the
molar ratio of the lithium-aluminum
oxide to the lithium-
cobalt oxide is (1-5): 1, and the
molar ratio of the lithium-aluminum oxide to the lithium-
cobalt oxide is (1-5): 1. And the
energy density, the high-temperature performance and the first efficiency are improved, so that the charge-
discharge rate performance of the battery is improved, the
power output capability of the battery is enhanced, and the battery has relatively good
flame retardance and also has the safety performance of the battery.