Silicon oxycarbide-derived hierarchical porous carbon nanoparticles with tunable pore structure for lithium-sulfur batteries
Sung Eun Wang, Minji Kim, Jin‐Sung Park, Jin Woong Lee, Do Woong Yoon, Youngsin Kim, Jung‐Hyun Kim, Yun Chan Kang, Dae Soo Jung
Abstract
Most lithium-sulfur (Li-S) batteries have limited practical commercialization owing to extremely low S loading, insufficient cycle stability, and poor rate capability despite their high theoretical capacity. Herein, Li-S batteries with outstanding electrochemical performance under high S loading mass are achieved from hierarchical porous carbon nanoparticles (hPCNs) prepared via a scalable spray pyrolysis process. HPCNs are synthesized from organosilanol precursors, which contains phenyl and hydroxyl groups attached to silicon facilitating SiO x C y , SiO 4 , and carbon nanonetwork formations. SiO x C y and SiO 4 phases can produce abundant micro- and mesopores, respectively, using template method. Consequently, hPCNs show high surface area (2789 m 2 g −1 ) and pore volume (2.31 cm 3 g −1 ) allowing large amount of sulfur to be accommodated efficiently. When hPCN is applied as a multifunctional sulfur host, micropores can suppress lithium polysulfide dissolution, whereas mesopores can accommodate a large amount of sulfur, improving the energy density of the Li-S battery. In addition, the carbon nanonetworks improve redox kinetics with their excellent electrical conductivity. Therefore, sulfur-infiltrated hPCNs show a high initial capacity of 1229 mA h g −1 and a capacity retention of 74% after 400 cycles at 1C rate.