Web-structured graphitic carbon fiber felt as an interlayer for rechargeable lithium-sulfur batteries with highly improved cycling performance

Abstract

Graphitic carbon fiber felt (GCFF) with a crystalline graphitic carbon structure was facilely prepared by a combination of electrospinning and graphitization (2800 degrees C heat treatment) and was used as an inter layer between the cathode and separator in Li-S batteries. This GCFF interlayer trapped the polysulfides on the cathode side and increased the utilization of sulfur by suppressing the shuttle phenomenon. Also, the GCFF was shown to be able to act as an upper current collector to reduce the charge-transfer resistance owing to the high crystallinity of the graphitic carbon fibers. The sulfur cathode with the GCFF interlayer showed a high specific initial discharge capacity of 1280.14 mAh g(-1) and excellent cycling stability (1004.62 mAh g(-1) after 100 cycles) at 0.2 C. Also, an image of the glass fiber (GF) separator on the anode side confirmed the presence of an SEI after 200 cycles, which apparently resulted from stable Li deposition on the Li metal because of the low or medium concentration of sulfur in the electrolyte solution. Our observations should contribute to elucidating the key features of complex threedimensional carbon fabrics with crystalline graphitic structures that allow them, when inserted as interlayers, to markedly improve the performance of rechargeable batteries. (C) 2017 Elsevier B.V. All rights reserved.