Synthesis and electrochemical performance of a polymer-derived silicon oxycarbide/boron nitride nanotube composite

Abstract

Polymer-derived ceramics (PDCs) such as silicon oxycarbide (SiOC) have shown promise as electrode materials for rechargeable Li-ion batteries (LIBs) owing to the synergy between their disordered carbon phase and hybrid bonds of silicon with oxygen and carbon. This study describes the synthesis and characterization of a new type of PDC composite comprising SiOC embedded with varying wt% of boron nitride nanotubes (BNNTs) and supported on reduced graphene oxide. Electron microscopy and a range of spectroscopic characterization techniques were employed to confirm the polymer-to-ceramic transformation and presence of a disordered carbon phase. The composites were tested as electrode materials for LIB and symmetric supercapacitor applications. As an electrode material for LIB, SiOC-BNNT paper composite containing 0.25 wt% BNNT demonstrated the highest charge capacity of 410 mA h g À1 (at 100 mA g À1 ) which stabilized at 238 mA h g À1 . On the contrary, composite electrode with 0.5 wt% BNNT demonstrated the highest specific capacitance corresponding to 78.93 F g À1 at 1 A g À1 with a cyclic retention of 86% after 185 cycles. This study shows that presence of BNNTs in the composite influenced the free carbon phase in SiOC and its electrochemical performance. As such, the composite may be used as a flexible electrode material for electrochemical energy storage devices.

Dielectric properties of polymer‐derived ceramic reinforced with boron nitride nanotubes

“…Therefore, PDCs reinforced with BNNTs are expected to be excellent ceramic composites to meet the EM transparent application requirements. PDCs reinforced with BNNTs have shown improved thermal stability, 18 thermal conductivity, 18 and excellent electrochemical performance 47 . Herein, we report for the first time about the electrical and dielectric properties of BNNTs‐reinforced PDCs.…”

“…Especially, BNNTs possesses perfect electrical insulation 34‐36 and superb oxidation resistance, 37 which can be used to adjust the real relative permittivity and dielectric loss tangent of materials 38 . BNNTs therefore are excellent candidates 39 for reinforcing polymers, 38,40‐45 ceramics, 18,36,46‐49 and metals 50 …”

Thermal properties of polymer‐derived ceramic reinforced with boron nitride nanotubes

“…For instance, PDC SiCN with only 6.4 vol.% CNTs shows over 150 % increase in hardness relative to monolithic PDC SiCN . PDC SiOC with 0.5 wt% NNT demonstrates a specific capacitance corresponding to 78.93 F·g −1 at 1 A·g −1 with a cyclic retention of 86% after 185 cycles …”

“…13 PDC SiOC with 0.5 wt% NNT demonstrates a specific capacitance corresponding to 78.93 F·g −1 at 1 A·g −1 with a cyclic retention of 86% after 185 cycles. 19 In this study, we report the thermal properties of BNNTreinforced ceramic composites with a high volume fraction of BNNT (up to 35.4 vol.%) using the PDC processing routine. The synthesized ceramic composites in this work possess exceptional thermal properties, including a high thermal conductivity of 4.123 W/(m·K) at room temperature, improved by 2100 % compared to that of pristine PDC.…”

Silicon Oxycarbide-Graphite Electrodes for High-Power Energy Storage Devices

“…On the other hand, the C1s spectra of the pure ceramic sample and SiOC/graphite composite show some differences in the share of particular bonds. Both C1s spectra ( Figure S2 ) were deconvoluted with four peaks at BE: 284.0–284.4 eV, 285.2–285.4 eV, 286.5–286.7 eV and 288.8–289.2 eV, which may be attributed to C-Si/C=C, C-C/C-H, C-O and C=O bonds, respectively [ 54 , 55 , 56 , 57 ]. However, the C1s spectrum of the SiOC/graphite composite shows a significantly larger peak corresponding to the C-C bond, and smaller peaks assigned to the C-Si, C-O and C=O bonds, which is related to a high graphite content in the composite.…”