Compact Sulfurized-Polyacrylonitrile/Graphene Composite Cathode for High-Energy and Long-Life Li-S Batteries

Abstract

Next-generation batteries have been in the spotlight to meet the demand for batteries with higher energy densities than commercial lithium-ion batteries. Among them, lithium-sulfur batteries have been actively investigated owing to their attractive features; 1) Ultrahigh energy density, 2) Low cost of sulfur. Herein, we propose a compact, high-performance, 2D sulfurized-polyacrylonitrile/graphene (2D-SPAN/G) cathode for practical Li–S batteries. A 2D-SPAN/G cathode with a high active-mass (sulfur) loading of 10 mg cm−2 is successfully prepared via high-pressure pelletization. In the 2D-SPAN/G cathode, graphene nanosheets function as a robust and conductive scaffold, which uniformly encapsulates SPAN nanoparticles, providing structural integrity and enabling the high electrochemical utilization of sulfur. Combined with the stabilized lithium metal anode by using a modified electrolyte (consisting of 1 M LiPF6 and 0.05 M LiDFOB in EMC:FEC (3:1 (v/v))), and a 2D-SPAN/G cathode delivers a high areal capacity of 11 mAh cm−2 and demonstrats outstanding cycling stability over 300 cycles at a high current density of 4 mA cm−2. Moreover, the excellent electrochemical performance of a scaled-up, pouch-type Li–S battery featuring a 2D-SPAN/G cathode demonstrats the viability of the proposed cathode. The reversibility of the Li+-ion storage mechanism of the 2D-SPAN/G cathode is confirmed using operando Raman spectroscopy. Reference s : [1] J.-Y. Hwang, S.-J. Park, C. S. Yoon and Y.-K. Sun, Energy Environ. Sci., 2019, 12, 2174–2184.[2] H. Kim, S. Bang, K.-J. Min, Y.-G. Ham, S.-J. Park and Y.-K. Sun, ACS Appl. Mater. Interfaces, 2021, 13, 39435–39445.[3] H. M. Kim, J.-Y. Hwang, D. Aurbach and Y.-K. Sun, J. Phys. Chem. Lett., 2017, 8, 5331–5337.