Preparation and Characterization of Core-Shell Structure Hard Carbon/Si-Carbon Composites with Multiple Shell Structures as Anode Materials for Lithium-Ion Batteries

Abstract

Novel core-shell structure hard carbon/Si-carbon composites are prepared, and their electrochemical performances as an anode material for lithium-ion batteries are reported. Three different types of shell coating are applied using Si-carbon, Si-carbon black-carbon and Si-carbon black-carbon/graphite nanosheets. It appears that the use of n-Si/carbon black/carbon composite particles in place of n-Si for the shell coating is of great importance to achieve enhanced electrochemical performances from the core-shell composite samples, and additional wrapping with graphite nanosheets leads to a more stable cycle performance of the core-shell composites.

Structural Control and Optimization Schemes of Silicon‐Based Anode Materials

“…This indicates that SCB and graphite nanoflakes can reduce the irreversible reaction of the active material with the electrolyte, thus improving the electrode's cycling stability and electrical conductivity. [ 92 ]…”

“…This indicates that SCB and graphite nanoflakes can reduce the irreversible reaction of the active material with the electrolyte, thus improving the electrode's cycling stability and electrical conductivity. [92] Recently, Yu-Qian Wang et al designed an improved siliconnickel nanoparticle based on a core-shell structure, which was dispersed on a three-dimensionally entangled carbon nanotube network (Si@Ni-NP/CNTs) by nitric acid pretreatment and aminofunctionalization. The silicon core nanoparticles (Si@Ni-NP) have a supportive effect and prevent the volume expansion of silicon, which ultimately reduces the degree of pulverization.…”

“…d) TEM micrographs; image of SCB, corresponding elemental mapping of carbon and silicon. Reproduced with permission [92]. Copyright 2021, The Authors.…”

Ionically Conductive Self-Healing Polymer Binders with Poly(ether-thioureas) Segments for High-Performance Silicon Anodes in Lithium-Ion Batteries

“…To meet the ever-increasing energy density requirements of electric energy storage and all-electric vehicles in the future, various high-capacity anode materials are being extensively developed. − Among them, Si is regarded as one of the most promising anode materials due to its high theoretical capacity (4200 mAh g –1 ), a low discharge plateau (around 0.4 V vs Li/Li + ), and abundant reserves on earth. − However, in the process of repeated charging and discharging, the huge volume expansion causes the Si anode to rupture and crush, loss of electrical contact between the active material and the current collector, and growth of an unstable solid electrolyte interphase (SEI). − These problems severely limit the commercialization of Si anodes. Various structural designs related to Si active materials, including core-shell structures, − nanosheets, − micron-thick Si films, porous frameworks, and yolk-shell nanoparticles, − can avoid mechanical fragmentation both at the electrode and particle levels. Such a nanostructured Si anode has been demonstrated to boost cycle performance considerably.…”

Scalable Synthesis and Electrochemical Properties of Porous Si-CoSi2-C Composites as an Anode for Li-ion Batteries

“…For example, downsizing Si particles to nanoscale and incorporating structures like nanospheres, nanowires, and nanotubes can alleviate volume changes [5][6][7][8][9]. Moreover, Si has been prepared in the form of composites and/or compounds with secondary phases of carbon or inactive/less active to Li + ions; these include materials such as Cu, Ni, Fe, SiN, Al 2 O 3 , Nb 2 O 5 , TiO 2 , and SiO x [10][11][12][13][14][15][16][17][18][19][20][21][22].…”