Three-dimensional architecture of lithium-anodes made from graphite fibers coated with thin-films of silicon oxycarbide: Design, performance and manufacturability

Abstract

Silicon oxycarbide (SiCO) is an amorphous molecular network of Si-CO tetrahedra anchored to graphene-like carbon. The graphene forms a three dimensional cellular network with a domain size of ~5 nm. Therefore nanometer thick films of SiCO grown on graphite may be expected to have unusual behavior. We grow these films on a bed of commercially available graphite fibers that serve the dual function of a current collector. The electrochemical behavior of the composite is measured as a function of the thickness of the SiCO films. Thick films approach the typical behavior of bulk SiCO (which has three times the capacity of graphite, but suffers from poor first cycle efficiency). However, films, approximately 100 nm thick, show high first cycle efficiency as well as high capacity. The composite performs better than the prediction from the rule-of-mixtures, which further substantiates the unusual behavior of the thin-film architecture. The Raman spectra of these thin films also differ from bulk SiCO. The development of thin graphite fibers, with a high surface to volume ratio that have the same capacity as the current graphite-powder technology, coupled with manufacturing of these thin-films by a liquid-polymer precursor based process, can propel these results toward commercialization.

A review of silicon oxycarbide ceramics as next generation anode materials for lithium-ion batteries and other electrochemical applications

“…Thin lms of SiOC are reported to perform better than their bulk counterparts. 106,144 At very high C rates, these thin-lm SiOC anodes exhibited a reversible storage capacity of 1000 mA h g −1 . Thin lms of these ceramics were fabricated by spray depositing the polymeric precursor on Cu, and then they were converted to a ceramic by pyrolysing them at 1000 °C.…”

“…Even though disordered carbon is commonly found in these systems, its discrete distribution in the SiOC matrix and disordered structure result in poor conductivity. 83,101,102 The solution to this problem is to produce composite anodes with SiOC mixed with various carbonaceous nanomaterials such as graphite, [103][104][105][106] carbon nanotubes, 32,107,108 carbon nanobers, 13,109-111 graphene 33,[112][113][114][115][116][117][118][119][120] and reduced graphene oxide. 121,122 Graphene, however, is widely explored among these carbonaceous materials due to its high electrical conductivity.…”

Electrochemical Performance of Polymer-Derived Silicon-Oxycarbide/Graphene Nanoplatelet Composites for High-Performance Li-Ion Batteries

“…By forming a percolation network, carbonaceous materials boost the electrical conductivity of the system as well as enhance Li storage capacity and electron transfer kinetics. Numerous studies have focused on the incorporation of carbon materials into the SiOC material system, including carbon nanotubes, , graphite, − graphene nanoplatelets (GNPs), − graphene oxide, , reduced graphene oxide, − and carbon nanofibers. , Various processing methods have been employed to develop 2D carbonaceous-based SiOC anodes, like ball milling, physical mixing, sol–gel infiltration, precursor infiltration, in situ reaction, and electrospinning. ,− ,, …”

Preparation and anti-oxidation performance of Al2O3-containing TaSi2–MoSi2–borosilicate glass coating on porous SiCO ceramic composites for thermal protection

“…The single-phase glass coating, reaction cured glass coating (RCG), toughened uni-piece fibrous insulation coating (TUFI) and high-efficiency tantalum-based ceramic composite (HETC) have been investigated successively. 13 According to the US patents, 14,15 the multilayer structure of single-phase glass coating needs to be sintered repeatedly and has a poor thermal shock resistance. RCG is applied on the first generation of rigid thermal insulation (LI).…”