In-situ constructing 3D nanocarbon conduction conformal network on silicon anodes for high-performance sulfide-based all-solid-state batteries

Due to swelling effects, the development of silicon anodes for lithium-ion batteries has been largely hampered by structural and interfacial instability. To implement the growing demand for higher energy density all-solid-state batteries (ASSBs), further improving the stability of the silicon anode structure is the key to breaking through the bottleneck. Here, we synthesize a silicon electrode coated by the conductive nanocarbon layer via in situ electrochemical processes. A 3D fast Li⁺-electron conduction conformal network composed of nanocarbon and polyvinylidene fluoride (PVDF) is constructed during cycling, expanding the active area and reducing stress concentrations, which leads to reinforced electrode kinetics and mechanical stability. Advanced focused ion beam-scanning electron microscope (FIB-SEM) and high-resolution transmission electron microscope (HRTEM) reveal that harmful phenomena such as electrode cracks, interfacial detachment, and lattice distortion are extremely suppressed, thus significantly enhancing the long-term cycling stability of ASSBs. In particular, the ASSBs assembled with a nano-metric Li_1.175Nb_0.645Ti_0.4O₃ (LNTO) coated LiCoO₂ (LCO) cathode and sulfide electrolytes offer superior long-cycle stability (0.8C for 450 cycles, 80.2%) and rate performance (2C for 1340 cycles, 73.1%).