Conducting Polymer Paper‐Based Cathodes for High‐Areal‐Capacity Lithium–Organic Batteries

Abstract

Conducting polymers have been considered for use as cathode materials in rechargeable lithium‐ion batteries (LIBs) since 1981 but problems with poor cycling stability, rapid self‐discharge, and low energy and power densities have so far limited their applicability. Herein it is shown that nanostructured freestanding conducting polymer composites [e.g., polypyrrole (PPy) and polyaniline (PANI)] can be used to circumvent these shortcomings. Freestanding and binder‐free PPy and cellulose‐based composites can straightforwardly be used as versatile organic cathode materials for LIBs. The composite, reinforced with chopped carbon filaments (CCFs), exhibited a large active mass loading of approximately 10 mg cm−2, an areal capacity of 1.0 mAh cm−2 (corresponding to 102 mAh g−1), and stable cycling. With an active mass loading of 4.4 mg cm−2, a capacity of 0.22 mAh cm−2 (corresponding to 58 mAh g−1) was found for current densities of 5 A g−1 yielding discharge times of approximately 40 seconds, and a capacity retention of 91 % over 100 cycles was obtained at 0.2 A g−1. The present method constitutes a straightforward approach for the manufacturing of high‐performance freestanding electroactive conducting‐polymer‐based paper‐like electrodes for use in inexpensive and sustainable, high‐performance organic LIBs.

Flexible Freestanding MoO3−x–Carbon Nanotubes–Nanocellulose Paper Electrodes for Charge‐Storage Applications

“…The flexible freestanding electrodes were prepared according to the previously reported protocol, [23,24] with some modification as explained below.I nat ypical experiment, MoO 3Àx nanosheet powder (70 mg, prepared as previously described), [28] multi-walled CNTs( 20 mg), and Cladophora cellulose (10 mg) were added to a mixture containing water (60 mL) and ethanol (20 mL). The obtained mixture was subjected to sonication for 20 min by using high-energy ultrasonic equipment (Sonics and Materials Inc.,U SA, Vibra-Cell 750) under water cooling.…”

“…In the last few years, nanocellulose has been used to fabricate paper‐based flexible electrodes for energy‐storage applications, owing to its resource abundance, high mechanical flexibility, and excellent solution processability . Although many methods have been used to prepare paper‐based electrodes, including printing methods, vaporization methods, and vacuum‐filtration methods, Wang et al . recently introduced a robust synthesis protocol for the manufacturing of flexible freestanding paper electrodes by using a combination of a redox‐active material, carbon nanotubes (CNTs), and Cladophora cellulose (CC).…”

“…The limited thickness of the active material meant that the capacities of the electrodes were relatively low, and because the electrodes also could be cycled for only approximately 2000 cycles, it was immediately clear that another electrode manufacturing approach would be required to allow this type of electrodes be used in energy‐storage devices, that is, a method that enables the increase of the active material thickness and stabilizes the long‐term cycling. One approach to increase the performance of these electrodes could be to mix the molybdenum trioxide with a conductive additive such as a carbonaceous material (e.g., graphene or CNTs), and nanocellulose to yield flexible and freestanding paper electrodes by using the approach recently employed to make conductive nanofiber networks composed of CNTs and nanocellulose …”

“…[13,14] In the last few years, nanocellulose has been used to fabricate paper-basedf lexible electrodes for energy-storagea pplications, owing to its resource abundance,high mechanical flexibility,and excellent solution processability. [10,[16][17][18][19][20][21][22] Although many methods have been used to preparep aper-basede lectrodes, including printing methods, vaporization methods, and vacuum-filtration methods, [17,22] Wang et al [23,24] recently introduced ar obust Herein, ao ne-step synthesis protocol was developed for synthesizing freestanding/flexible paper electrodes composed of nanostructured molybdenum oxide (MoO 3Àx )e mbedded in a carbon nanotube (CNT) and Cladophora cellulose (CC) matrix. The preparation methodi nvolved sonication of the precursors, nanostructured MoO 3Àx ,C NTs, and CC with weight ratios of 7:2:1, in aw ater/ethanol mixture, followed by vacuum filtration.…”

“…One approach to increaset he performance of these electrodes could be to mix the molybdenumt rioxide with a conductive additive such as ac arbonaceous material (e.g.,g raphene or CNTs), [32,33,41] and nanocelluloset o yield flexible and freestanding paper electrodes by using the approachr ecently employed to make conductive nanofiber networks composed of CNTsa nd nanocellulose. [23,24] The present work describes as traightforward approach for the manufacturing of porous, freestanding, and flexible electrodes composed of MoO 3Àx -CNTs-CC, in which the CC serves as ad ispersing agent and flexible substrate, whereas the CNTsa ct as ac onductive additive. The electrodes were tested in 1.0 m H 2 SO 4 and cycled between 0a nd 0.5 Vv s. Ag/AgCl( 1m KCl).…”