Electrospun Core–Shell Fibers for Robust Silicon Nanoparticle-Based Lithium Ion Battery Anodes

Abstract

Because of its unprecedented theoretical capacity near 4000 mAh/g, which is approximately 10-fold larger compared to those of the current commercial graphite anodes, silicon has been the most promising anode for lithium ion batteries, particularly targeting large-scale energy storage applications including electrical vehicles and utility grids. Nevertheless, Si suffers from its short cycle life as well as the limitation for scalable electrode fabrication. Herein, we develop an electrospinning process to produce core-shell fiber electrodes using a dual nozzle in a scalable manner. In the core-shell fibers, commercially available nanoparticles in the core are wrapped by the carbon shell. The unique core-shell structure resolves various issues of Si anode operations, such as pulverization, vulnerable contacts between Si and carbon conductors, and an unstable sold-electrolyte interphase, thereby exhibiting outstanding cell performance: a gravimetric capacity as high as 1384 mAh/g, a 5 min discharging rate capability while retaining 721 mAh/g, and cycle life of 300 cycles with almost no capacity loss. The electrospun core-shell one-dimensional fibers suggest a new design principle for robust and scalable lithium battery electrodes suffering from volume expansion.

Microwave-Assisted Oxidation of Electrospun Turbostratic Carbon Nanofibers for Tailoring Energy Storage Capabilities

“…Microwave irradiation, which reduces reaction time dramatically due to the unique microwave dielectric heating mechanism, [24] has enabled efficient preparation and modification of various materials such as metal-organic frameworks, [25] graphene sheets, [26] nanoparticles, [27] and metal oxide/graphene hybrids. [28] However, to the best of our knowledge, microwave-assisted oxidation of ECNFs has not yet been documented, as noted in the comprehensive review of structure modification strategies for ECNFs by Inagaki et al [13] Common methods to control ECNF structures and properties include variation of carbonization conditions [15,20,21] and incorporation of functional ingredients such as Pd, [16] Si, [17] Sn, [18] and Pt [29] nanoparticles. Polyacrylonitrile (PAN)-derived ECNFs [21,23] are structurally different from CNTs and graphite [7][8][9] in that they exhibit turbostratic carbon structures with nanosized graphite domains and abundant edge defects.…”

Mesoporous silicon sponge as an anti-pulverization structure for high-performance lithium-ion battery anodes

“…Among all the candidates for anode materials, silicon (Si) has a theoretical specific capacity of B4,200 mAh g À 1 (Li 22 Si 5 ), B11 times of the theoretical specific capacity of the state-of-theart graphite anode, and it does not have the safety concern of lithium metal dendrite formation 3 . Therefore, Si has been regarded as one of the most promising anode materials for next-generation Li-ion batteries.…”

Dry-air-stable lithium silicide–lithium oxide core–shell nanoparticles as high-capacity prelithiation reagents

“…For example, Si is a particularly attractive anode material, owing to its high specific capacity of B4,200 mAh g À 1 , excellent material abundance and well-developed industrial infrastructure for manufacturing 16,18 . In the past several years, there has been exciting progress in addressing the issues associated with large volume change (4300%) during lithium insertion and extraction by designing nanostructured Si including nanowires and coreshell nanowires [19][20][21][22] , hollow particles and tubes [23][24][25] , porous materials 26,27 , Si/C nanocomposites [28][29][30] and by using novel binders [31][32][33][34] . One of the remaining issues for Si anodes is the large capacity loss in the first cycle.…”