High Mass-Loading Sulfur-Composite Cathode for Lithium-Sulfur Batteries

Abstract

The development of electric vehicles and portable devices require high power and high energy density batteries. In this regard, among the existing energy storage systems, the lithium-ion batteries (LIBs) play a key role. However, the energy and power densities of conventional LIBs are reaching the limited theoretical values and cannot fulfill requirements for new generation portable devices and electric vehicles. Sulfur is a promising replacement for intercalated cathode materials, since it has high theoretical capacity of 1672 mAh g -1 and high gravimetric energy density of 2600 Wh kg -1 . 1 Moreover sulfur has several advantages such as low cost, environmental friendliness and abundance. 2 However, commercialization of lithium-sulfur batteries faces several difficulties related to low conductivity of sulfur, polysulfide dissolution and lithium dendrite growth. 3,4 The aim of this research was to increase mass loading of sulfur in the electrode, which in turn requires improvement in the bulk conductivity. For that reason, high sulfur loading S/DPAN/CNT composite cathode was prepared by a simple and efficient way of designing micro and nano level 3D carbon networks. The covalent bonding between pyrolyzed PAN and sulfur diminishes polysulfide dissolution, while CNT maintains structural integrity, acting as nanoscale interwoven skeleton and ensures electron transfer within and between S/DPAN granules. 5 Then S/DPAN/CNT was impregnated into pores of commercial carbon fiber paper (CFP), which in its turn provides bulk electron conductivity in macro level. As a result, mass loading of sulfur was increased up to 5 mg cm -2 while maintaining a high initial specific capacity of 1400 mAh g -1 and stable cyclability. Acknowledgements This research was supported by the targeted state program BR05236524 “Innovative Materials and Systems for Energy Conversion and Storage” from the Ministry of Education and Science of the Republic of Kazakhstan for 2018-2020. References: [1] K.H. Shin, K.-B. Kim, C.S. Jin, W. Ahn, K.N. Jung, J. Power Sources 202 (2011) 394–399. [2] Y. Zhang, Y. Zhao, T. N. L. Doan, A. Konarov, D. Gosselink, H. G. Soboleski, P. Chen, Solid State Ionics 238 (2013) 30–35. [3] M. Li, R. Carter, A. Douglas, L. Oakes, C. L. Pint, ACS Nano 11 (2017) 4877–4884. [4] Z. Nie, J.-G. Zhang, N. D. Browning, Q. Li, L. B. Mehdi, X. Xie, J. Liu, G. L. Graff, J. Zheng, S. Ferrara, Adv. Energy Mater. 5 (2015) 1402290.