Effects of annealing temperature on electrochemical performance of SnSx embedded in hierarchical porous carbon with N-carbon coating by in-situ structural phase transformation as anodes for lithium ion batteries

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 SnS2, 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.