Enhanced Li-Ion Rate Capability and Stable Efficiency Enabled by MoSe2 Nanosheets in Polymer-Derived Silicon Oxycarbide Fiber Electrodes

Abstract

Transition metal dichalcogenides (TMDs) such as MoSe2 have continued to generate interest in the engineering community because of their unique layered morphology—the strong in-plane chemical bonding between transition metal atoms sandwiched between two chalcogen atoms and the weak physical attraction between adjacent TMD layers provides them with not only chemical versatility but also a range of electronic, optical, and chemical properties that can be unlocked upon exfoliation into individual TMD layers. Such a layered morphology is particularly suitable for ion intercalation as well as for conversion chemistry with alkali metal ions for electrochemical energy storage applications. Nonetheless, host of issues including fast capacity decay arising due to volume changes and from TMD’s degradation reaction with electrolyte at low discharge potentials have restricted use in commercial batteries. One approach to overcome barriers associated with TMDs’ chemical stability functionalization of TMD surfaces by chemically robust precursor-derived ceramics or PDC materials, such as silicon oxycarbide (SiOC). SiOC-functionalized TMDs have shown to curb capacity degradation in TMD and improve long term cycling as Li-ion battery (LIBs) electrodes. Herein, we report synthesis of such a composite in which MoSe2 nanosheets are in SiOC matrix in a self-standing fiber mat configuration. This was achieved via electrospinning of TMD nanosheets suspended in pre-ceramic polymer followed by high temperature pyrolysis. Morphology and chemical composition of synthesized material was established by use of electron microscopy and spectroscopic technique. When tested as LIB electrode, the SiOC/MoSe2 fiber mats showed improved cycling stability over neat MoSe2 and neat SiOC electrodes. The freestanding composite electrode delivered a high charge capacity of 586 mAh g-1electrode with an initial coulombic efficiency of 58%. The composite electrode also showed good cycling stability over SiOC fiber mat electrode for over 100 cycles.

Recent advances in precursor-derived ceramics integrated with two-dimensional materials

“…96 A self-standing fiber which composed of MoSe 2 nanosheets embodied in SiOC matrix was prepared by electrospinning of MoSe 2 nanosheets suspended in polymeric precursor followed by pyrolysis. 97 This fibre composite showed stable coulombic efficiency and a higher capacity over neat SiOC electrodes.…”

Polymer-Derived Silicon Oxycarbide/Graphene Oxide Porous Ceramic Monoliths Obtained from Pickering Emulsions: Application as Active Electrodes for Lithium-Ion Batteries

“…Few drops of 1-methyl-2-pyrrolidinone (Sigma-Aldrich) were added until a homogeneous mixture was obtained. 33 Subsequently, a uniform thin film of approximately 125 μm was deposited on a 9 μm copper (current collector) substrate through the doctor blade technique and then dried for 18 h in an oven at 80 °C for solvent removal. After drying, a 7.94 mm circular punch was used to cut the composite electrodes, which were then used as a working electrode in the assembly of the CR 2023 type coin-shaped Li + half-cell.…”

“…The differential capacity curves of the SiOC-GO-R16 (900 °C) and nonporous SiOC (900 °C) composite electrodes showed distinct peaks during the first cycle of lithium insertion. 33 These peaks can be attributed to the decomposition of the electrolyte and the formation of the solid electrolyte interface (SEI) during the initial Li + -ion insertion process. 50 Remarkably, in the second cycle, the shape of the differential capacity curves remained consistent for all samples, with no peaks observed, indicating that the SEI had already been formed, in agreement with previous observations.…”

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

“…In place of carbonaceous materials, other elements like tin and 124–127 antimony 128,129 and in some cases transition metal dichalcogenides based on MoSe 2 (ref. 130) were explored as active fillers for improving the overall battery performance of SiOC anodes. The addition of Sn and Sb enhances the battery performance of SiOC anodes due to their high electrochemical activity.…”