Abstract:

Tuned tin chalcogenides rooted in hierarchical porous carbon (HPC) with N-carbon coating layers are prepared by thermal shock under various temperatures (denoted as HPC-SnS₂-PAN-Various T). With the increase of annealing temperature, the morphology and phase structure of SnS₂, as well as the cyclization degree of polyacrylonitrile (PAN), are significantly changed, which leads to the formation of rod-like SnS and ordered structure of conductive N-carbon layer. By combining HPC, N-carbon coating derived from the cyclization of PAN, with 1D SnS nanorods generated from structural phase transformation of SnS_2, the optimized composite (HPC-SnS₂-PAN-500) as anode for lithium ion batteries (LIBs) provides buffer space for volume changes during alloying/dealloying process, builds a highly conductive network as well as decreases irreversible capacity from solid electrolyte interphase and enhances the ion/electron transport. Attributed to the above merits from composition regulation and architecture modification by sulfur depletion and PAN cyclization, this target anode exhibits an extraordinary cycling stability with a high specific capacity of 652.5 mA h/g at 0.5 A/g after 900 cycles. It suggests that rod-like SnS embedded in HPC with cyclized PAN layers by thermal treatment approach renders a potential structural design of anode materials for LIBs.

Key words: Hierarchical porous carbon, SnS_x, Conducting medium, Cycling stability, Lithium ion batteries