Three-Dimensional Interconnected Spherical Graphene Framework/SnS Nanocomposite for Anode Material with Superior Lithium Storage Performance: Complete Reversibility of Li₂S

Abstract

Three-dimensional (3D) interconnected spherical graphene framework-decorated SnS nanoparticles (3D SnS@SG) is synthesized by self-assembly of graphene oxide nanosheets and positively charged polystyrene/SnO nanospheres, followed by a controllable in situ sulfidation reaction during calcination. The SnS nanoparticles with diameters of ∼10-30 nm are anchored to the surface of the spherical graphene wall tightly and uniformly. Benefiting from the 3D interconnected spherical graphene framework and subtle SnS nanoparticles, the generated LiS could keep in close contact with Sn to make possible the in situ conversion reaction SnS + 2Li + 2e ↔ Sn + LiS. As a result, the 3D SnS@SG as the anode material for lithium ion batteries shows a high initial Coulombic efficiency of 75.3%. Apart from the irreversible capacity loss of 3D spherical graphene, the initial Coulombic efficiency of SnS in the 3D SnS@SG composite is as high as 99.7%, demonstrating the almost complete reversibility of LiS in this system. Furthermore, it also exhibits an excellent reversible capacity (800 mAh g after 100 cycles at 0.1 C and 527.1 mAh g after 300 cycles at 1 °C) and outstanding rate capability (380 mAh g at 5 °C).

Hollow Spheres Consisting of SnS Nanosheets Conformally Coated with S‐Doped Carbon for Advanced Lithium‐/Sodium‐Ion Battery Anodes

“…The Li storage characteristics of recently reported SnS/C composites for LIBs (Figure d) indicate the advantages of the SnS@C HSs electrode . Figure e shows the Nyquist impedance plots of SnS@C HSs and bare SnS after 11 cycles in a fully charged state.…”

“…In the first cathodic process, the peak near 1.05 V corresponds to the conversion reaction from SnS to Sn and Li 2 S as shown by Equation (1). [33] The SEI film formed in this potential range causes some irreversible capacity and a positive shift after the first sweep. The other peaks near 0.2 V arise from the alloying process of Li x Sn [Eq.…”

“…Figure S9a shows the CV plots of the five cycles of SnS@C HSs at scanning rate of 0.1 mV s −1 in a potential range between 0.01 and 3.0 V (vs. Li + /Li). In the first cathodic process, the peak near 1.05 V corresponds to the conversion reaction from SnS to Sn and Li 2 S as shown by Equation (1) . The SEI film formed in this potential range causes some irreversible capacity and a positive shift after the first sweep.…”

“…The other peaks near 0.2 V arise from the alloying process of Li x Sn [Eq. ] …”

“…In the delithiation process, the anodic peaks between 0.6‐0.7 V in the first sweep arise from the de‐alloying process of Li x Sn to Sn and the peaks at 1.25 and 1.9 V show the back‐conversion process from Sn and Li 2 S to SnS . For comparison, the 5 th CV curve of SnS@C HSs and bare SnS are shown in Figure a.…”