Electrochemical Performance of Carbon-Rich Silicon Carbonitride Ceramic as Support for Sulfur Cathode in Lithium Sulfur Battery

Abstract

As a promising matrix material for anchoring sulfur in the cathode for lithium-sulfur (Li-S) batteries, porous conducting supports have gained much attention. In this work, sulfur-containing C-rich SiCN composites are processed from silicon carbonitride (SiCN) ceramics, synthesized at temperatures from 800 to 1100 °C. To embed sulfur in the porous SiCN matrix, an easy and scalable procedure, denoted as melting-diffusion method, is applied. Accordingly, sulfur is infiltrated under solvothermal conditions at 155 °C into pores of carbon-rich silicon carbonitride (C-rich SiCN). The impact of the initial porosity and microstructure of the SiCN ceramics on the electrochemical performance of the synthesized SiCN-sulfur (SiCN-S) composites is analysed and discussed. A combination of the mesoporous character of SiCN and presence of a disordered free carbon phase makes the electrochemical performance of the SiCN matrix obtained at 900 °C superior to that of SiCN synthesized at lower and higher temperatures. A capacity value of more than 195 mAh/g over 50 cycles at a high sulfur content of 66 wt.% is achieved.

Polymer‐Derived Ceramic Aerogels to Immobilize Sulfur for Li‐S Batteries

“…As a matter of fact, it has been demonstrated that efficiencies outbreaking 100% are observed when soluble polysulfides are shuttled toward the anode, where sulfur oxidation releases the excess charge responsible for the efficiency boost. [ 22,23 ]…”

“…As a matter of fact, it has been demonstrated that efficiencies outbreaking 100% are observed when soluble polysulfides are shuttled toward the anode, where sulfur oxidation releases the excess charge responsible for the efficiency boost. [22,23] We report the coulombic efficiency of SiOC-A, SiCN-A, and spSiOC in Figure 6b. Evidently, silicon oxycarbide-based cathodes show an increase in the efficiency toward 140% and 120% for the SiOC-A and spSiOC, respectively, which remain stable from the 60 th and 30 th cycle on, respectively.…”

“…[21] Porous C-rich Si-based PDCs have been also investigated as a confinement material in S cathodes. [22][23][24] In this work, we studied the electrochemical performance of three different sulfur/PDC cathodes. For two of them sulfur is contained in PDCs aerogels belonging to the Si-O-C and Si-C-N systems, respectively, obtained via CO 2 supercritical drying [9,25] while in the third one sulfur is confined in a mesoporous SiOC processed via the "polymeric spacer" method.…”

“…[ 21 ] Porous C‐rich Si‐based PDCs have been also investigated as a confinement material in S cathodes. [ 22–24 ]…”

Structure and Electrical Properties of Carbon-Rich Polymer Derived Silicon Carbonitride (SiCN)

“…Consequently, the electrical conductivity of semiconductor engineering ceramics can also be modified through the choice of pyrolysis atmosphere. So far, some applications of electrically conducting carbon rich PDCs where tailoring the chemical composition could influence the properties of the ceramics and make them of functional use have been displayed in batteries or electrocatalysis [29][30][31]. Motivated by the exceptional properties of carbon rich PDCs that have evolved in the recent past and the high temperatures stability of SiCN PDCs, it is believed that a tailor-made chemical composition of carbon rich SiCN could hold prospects for novel discoveries in other application areas such as thermopower or high temperature electronics that requires basically p-type and n-type semiconductors.…”