Improved electrochemical performance of soft carbon derived from coal liquefaction residue coated with expanded graphite for Lithium/Potassium batteries
Xiao Li, Qian Chu, Deyang Zhao, Chunhua Chen, Yuming Cui, Wenlong Xu, Yulin Li, Xiaodong Tian, Tao Yang
Abstract
This study investigated the use of asphaltene from coal liquefaction residue (CLRA) as a precursor for creating carbon nanosheets, which were then used to create a unique sandwich structure of soft carbon (SC) coated with expanded graphite (EG) composite (SC@EG) anodes for both lithium-ion and potassium-ion batteries. The SC@EG was formed through a covalent bond between EG and SC, resulting in a porous structure with favorable porosity and copious defects that expedited the migration of both Li + and K + ions. The SC@EG showed good electrochemical properties including high reversible capacity (510 mAh/g at 0.5 A/g in LIBs and 268 mAh/g at 0.1 A/g in KIBs), good rate performance (172 mAh/g at 4 A/g in LIBs and 154 mAh/g at 1 A/g in KIBs) and cyclic stability, attributed to the exceptional electronic conductivity and profound porosity of the structure.