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 stored 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 were confirmed via synchrotron high-pressure powder X-ray diffraction, atomic force microscope, and low-dose transmission electron microscopy. The 1, 2, 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 (SEI, 6 nm, Cyro-TEM) was oriented construction in ester electrolyte. Benefited from the synergistic effect of bulk phase and SEI, the obtained 3-monolayer SnS₂ anode achieved fast-charging capacity of 300 mAh g^-1 at 30 A g^-1 with 36 seconds, exhibiting new height of fast-charging ability in SIBs. Meanwhile. it performed long-cycling stability with negligible capacity decay for 600 cycles. The assembled pouch cell with Na₃V₂(PO₄)2F₃ cathode showed high-energy-density of about 187.5 Wh kg⁻¹. The atomic-layer leveled regulation method paves a way for precise synthesis of materials at the atomic level and oriented design of fast-charging rechargeable batteries.