Self-limited atomic-layer tin-sulfides with high-electron-intensity interface induced ultrathin SEI for fast-charging sodium-ion batteries

Fast-charging batteries that can be charged in minutes and store enough energy are highly desired in the electric vehicle and grid storage, but are usually limited to the electrodes with lower carrier diffusion. Herein, self-limited 1, 2, and 3 monolayers SnS2 on the graphene were fabricated as fast-charging anodes for sodium-ion batteries (SIBs). The tunable atomically-thin SnS2 compound was confirmed using synchrotron high-pressure powder X-ray diffraction, atomic force microscopy, and low-dose transmission electron microscopy (TEM). The 1, 2, and 3 atomic-layer SnS2 showed ultra-high phase contact of discharged products; thus, high bulk Na+/electronic conductivity was acquired. Simultaneously, ultra-thin and NaF, Na2CO3-riched solid-electrolyte interphase (6 nm, Cyro-TEM) was oriented construction in ester electrolyte. Benefiting from the synergistic effect of bulk phase and solid-electrolyte interphase, the obtained 3-monolayer SnS2 anode achieved a fast-charging capacity of 300 mAh·g-1 at 30 A·g-1 within 36 s, exhibiting new height of fast-charging ability in SIBs. Meanwhile, it demonstrated long-cycling stability with negligible capacity decay for 600 cycles. The assembled pouch cell with Na3V2(PO4)2F3 cathode showed a high-energy density of about 187.5 Wh·kg-1. The atomic-layer leveled regulation method paves the way for precise synthesis of materials at the atomic level and oriented design of fast-charging rechargeable batteries.