Carbon Nanotube Web with Carboxylated Polythiophene “Assist” for High-Performance Battery Electrodes

Abstract

A carbon nanotube (CNT) web electrode comprising magnetite spheres and few-walled carbon nanotubes (FWNTs) linked by the carboxylated conjugated polymer, poly[3-(potassium-4-butanoate) thiophene] (PPBT), was designed to demonstrate benefits derived from the rational consideration of electron/ion transport coupled with the surface chemistry of the electrode materials components. To maximize transport properties, the approach introduces monodispersed spherical FeO (sFeO) for uniform Li diffusion and a FWNT web electrode frame that affords characteristics of long-ranged electronic pathways and porous networks. The sFeO particles were used as a model high-capacity energy active material, owing to their well-defined chemistry with surface hydroxyl (-OH) functionalities that provide for facile detection of molecular interactions. PPBT, having a π-conjugated backbone and alkyl side chains substituted with carboxylate moieties, interacted with the FWNT π-electron-rich and hydroxylated sFeO surfaces, which enabled the formation of effective electrical bridges between the respective components, contributing to efficient electron transport and electrode stability. To further induce interactions between PPBT and the metal hydroxide surface, polyethylene glycol was coated onto the sFeO particles, allowing for facile materials dispersion and connectivity. Additionally, the introduction of carbon particles into the web electrode minimized sFeO aggregation and afforded more porous FWNT networks. As a consequence, the design of composite electrodes with rigorous consideration of specific molecular interactions induced by the surface chemistries favorably influenced electrochemical kinetics and electrode resistance, which afforded high-performance electrodes for battery applications.

Thin‐Film Electrode Design for High Volumetric Electrochemical Performance Using Metal Sputtering‐Combined Ligand Exchange Layer‐by‐Layer Assembly

“…The first cathodic sweep of the Pt‐sputtered electrode [i.e., Pt@(OA‐Fe 3 O 4 NP/TREN) 35 multilayer] showed two reduction peaks. The first reduction peak at 1.58 V versus Li may be due to the irreversible lithiation of Fe 3 O 4 NPs [Fe 3 O 4 + x Li + + x e − → Li x (Fe 3 O 4 ) up to x = 2], and the second peak at 0.65 V versus Li is ascribed to the subsequent conversion reaction of Fe 3 O 4 NPs [Li x (Fe 3 O 4 ) + (8− x ) Li + + (8− x )e − → 3Fe 0 + 4Li 2 O], including the formation of a solid electrolyte interphase (SEI) layer containing Li 2 O on the electrode surface resulting from the irreversible decomposition of electrolyte . The sequential anodic scan displayed a relatively broad peak at ≈1.66 V versus Li associated with the oxidation of Fe 0 to Fe 2+ /Fe 3+ by the delithiation process .…”

Polythiophene Grafted onto Single‐Wall Carbon Nanotubes through Oligo(ethylene oxide) Linkages for Supercapacitor Devices with Enhanced Electrochemical Performance

“…However, only weak interconnections by Van der Waals forces and hydrogen bonds were found between the two constituents by these conventional methods, which render poor compatibility as well as poor capacitance like previously reported PTh/MWCNT and PEDOT/MWCNTs composites . On the other hand, covalent functionalization of SWCNTs with PTh have been proved to realize an effective charge transfer process and enhance ionic transport . Indeed, very few previous studies have reported the effect of assembled architecture on electrochemical performance of PTh covalent functionalization of SWCNTs.…”

“…[15,17] On the other hand, covalent functionalization of SWCNTs with PTh have been proved to realize an effective charge transfer process and enhance ionic transport. [23][24] Indeed, very few previous studies have reported the effect of assembled architecture on electrochemical performance of PTh covalent functionalization of SWCNTs. Therefore, the "grafting to" approach is to be carried out for grafting PTh with functionalized SWCNTs with an aim to increase the electrochemical capacitance as well as lower the fabrication cost.…”

Structure Design and Composition Engineering of Carbon‐Based Nanomaterials for Lithium Energy Storage

“…A CNT network has demonstrated high‐rate capability without sacrificing performance. CNTs web electrodes comprising magnetite spheres offer a proper proof for this perspective . This freestanding CNTs web displayed high mechanical strength and long‐range conducting networks (25 S cm −1 ).…”

“…The self‐weaving behavior of CNTs to construct an interwoven conductive network allows fast transfer of electrons . A good example is a low‐density CNTs foam with high areal loading and areal capacity sulfur cathodes prepared via freeze‐drying . Vapor‐phase capillary infiltration of sulfur into this CNTs foam leads to a mass loading of 79%, showing a high sulfur areal loading of 19.1 mg cm −2 , and high areal capacity of 19.3 mAh cm −2 .…”