Electrospun core–shell silicon/carbon fibers with an internal honeycomb-like conductive carbon framework as an anode for lithium ion batteries

Abstract

Core-shell silicon/carbon (Si/C) fibers with an internal honeycomb-like carbon framework are prepared based on dual coaxial electrospinning. For this hierarchical structure, the fiber's core is composed of a porous carbon framework and embedded Si nanoparticles, which is further wrapped by a compact carbon shell. The well-defined Si/C composite anode shows high specific capacities, good capacity retention, and 10 high accessibility of Si in lithium-ion batteries. An initial reversible capacity of 997 mAh g -1 and a capacity retention of 71 % after 150 cycles are demonstrated with a current density of 0.2 A g -1 . At a higher current density of 0.5 A g -1 , a reversible capacity of 603 mAh g -1 can be maintained after 300 cycles. The accessibility of Si in the Si/C anode is up to 3612 mAh g -1 in the 1 st cycle. The excellent electrochemical properties are attributed to the hierarchical structure of Si/C fibers. The porous carbon 15 framework in the core region could not only accommodate the volume expansion of Si, but also enhance the conductivity inside these fibers. The compact carbon shell is able to prevent electrolyte from permeating into the core section, therefore a stable solid-electrolyte interphase can be formed on the fiber surface. 65

Silicon nanoparticles embedded in a porous carbon matrix as a high-performance anode for lithium-ion batteries

“…Two broad peaks at around 1.17 V and 0.45 V can be ascribed to the decomposition of electrolyte and formation of SEI layer can be observed in the first cathodic curve. 47,48 These peaks disappeared in the subsequent cycles. The sharp cathodic peak below 0.12 V indicates a Li alloying process from crystalline Si into amorphous Li x Si phase and a following crystallization to crystalline Li 15 Si 4 phase.…”

Raising Nanofiber Output: The Progress, Mechanisms, Challenges, and Reasons for the Pursuit

“…Electrospun core shell silicon/carbon nanofibers b) with an internal conductive carbon framework potential for anodes in lithium ion batteries. Reproduced with permission . Copyright 2015, RSC.…”

Electrospinning of Nanofibers for Energy Applications

“…It also can create connections between the fibers that are conducive to Li + ion transport. In other formats, a core-shell silicon/carbon fiber (Si/po-C@C) was prepared by simultaneously electrospinning polystyrene (PS)/PAN/Si as the core and electrospinning PAN as the shell then carbonization [82]. The structural design of the Si/po-C@C composite fiber is demonstrated in Figure 4.…”

“…(SEI: solid-electrolyte interphase). Reproduced with permission from [82]. Copyright Royal Society of Chemistry, 2015.…”