Optimizations of Graphitic Carbon/Silicon Hybrids for Scalable Preparation with High-Performance Lithium-Ion Storage
Xinrui Li, Haiping Su, Cheng Ma, Keming Hou, Jian Wang, Hongzhen Lin, Yazhuo Shang, Honglai Liu
Abstract
The Si/graphitic carbon composites display the promising future due to the high theoretical capacity of Si and the ultrahigh conductivity of carbonaceous materials. However, their practical applications have always been hindered by the complex synthesis, high cost, low production, and low utilization with large volumetric changes. Herein, different kinds of graphitic carbons (GCs) with different graphitization degrees and morphologies are optimized in a catalytic graphitization route at low temperature for large-scale preparation. Mixed with the silicon nanoparticles as anode materials, it is found that the initial Coulombic efficiency (ICE) is significantly enhanced along with the increasing degree of graphitization and electronic conductivity. The presence of fewer lattice defects also reduces the formation of SEI in the first discharge process, resulting in high utilization. As a consequence, the so-fabricated electrode exhibits an initial capacity of 2189 mA h g–1 and a capacity of 1081 mA h g–1 after 200 cycles. Moreover, with the help of the negligible weight of the covered carbon layer by chemical vapor deposition approach on the hybrid electrode, the optimized electrode delivers a reversible capacity of 996 mA h g–1 with improved capacity retention of 70.9% after 500 cycles, showing the great potential in the future.