Three-Dimensional, Chemically Bonded Polypyrrole/Bacterial Cellulose/Graphene Composites for High-Performance Supercapacitors

Abstract

Flexible energy storage systems have recently attracted great interest for portable electronic devices. The functionalization of graphene provides vast platform in tailoring its nanostructure and properties for energy storage via facile processing. Here we first demonstrate the development of chemically bonded graphene oxide and bacterial cellulose hybrid composite coated with polypyrrole for robust and high-efficiency supercapacitor electrodes. The as-prepared composites exhibited a highest electrical conductivity (1320 S m -1 ) and the largest volumetric capacitance (278 F cm -3 ) ever shown by carbon-based electrodes, along with 95.2% retention of 556 F g -1 gravimetric capacitance over 5000 recycling tests in asymmetric supercapacitors. Impressively, the hybrid electrode contributed a 492 F g -1 gravimetric capacitance and 93.5% retention over 2000 recycling in symmetric supercapacitors. The nanostructure and composition of the composites were found to play a crucial role for the performance of these three-dimensional, chemically bonded hybrid composite electrodes. INTRODUCTIONFlexible energy storage systems have recently attracted great interest for applications in portable electronic devices and hybrid electrical vehicles. 1 Supercapacitors (also called electrochemical capacitors) have been widely explored for energy storage application because of their higher power density, cycle efficiency, wide thermal operating range, and lower maintenance cost. 2-5 To date, supercapacitors can be subdivided into two classes: electrochemical double-layer capacitors (EDLCs) and pseudocapacitors. The EDLCs store the energy physically through the adsorption of ions on the surface of the electrodes, whereas pseudocapacitors enable electrochemical energy storage by fast redox reactions occurring between the electrode active material and the electrolyte. 1 Featuring large surface area (ca. 1000 m 2 g -1 ), activated carbon (AC) based electrodes, as the state-of-art electrodes for EDLCs, exhibit large gravimetric capacitance with electrostatic mechanism. However, the existence of large micro/macropores within AC proves to be disadvantageous for the adsorption of the electrolyte on the surface of electrodes, deteriorating the function of capacitors. 5 To address this challenge, intense research efforts have devoted to graphene (GE), a carbon monolayer packed into 2D honeycomb lattice, due to high theoretical surface area (2,630 m 2 g -1 ) 6 and theoretical capacitance (550 F g -1 ) 7 to boost the energy density of such devices. To create a large electrolyte-accessible area, porous graphene-like materials have been developed including GE foam/hydrogel, 8-10 crumpled/wrinkle GE, 11 graphene oxide (GO), 12 and reduced graphene oxide (rGO). 5 However, the lower gravimetric capacitance (100-270 F g -1 and 70-120 F g -1 with aqueous and organic electrolytes, respectively) 12,7 and random restacking of GE sheets make graphene-like materials electrodes uncompetitive to AC in

Polypyrrole/nickel sulfide/bacterial cellulose nanofibrous composite membranes for flexible supercapacitor electrodes

“…The C m is about 569, 713, and 651 F g -1 for PPy/NiS/BC-10, PPy/NiS/BC-50, and PPy/NiS/BC-100 at a current density of 0.8 mA cm -2 , respectively, which is higher than that for PPy/BC (502 F g -1 ). The highest value for PPy/NiS/BC-50 is even larger than the values of BC-based active materials reported in the literature, such as chemically bonded PPy/BC/graphene composites (556 F g -1 ;Liu et al 2015c), PPy/ BC/MWCNT (216.4 F g -1 ;Li et al 2014a), and PANI/BC/MWCNT (656 F g -1 ;Li et al 2014b). The cycling stability of the supercapacitors was tested by long-term GCD, as shown in…”

Nanostructured Polypyrrole-Based Ammonia and Volatile Organic Compound Sensors

“…Due to this high electrical conductivity and fast electron transport, CPs have also received great attention in the field of electrochemical high power energy storage devices such as supercapacitors [44]. Here, CPs are often combined with other materials, namely metal [45], metal oxides [46,47,48], and carbon materials such as carbon nanotubes and graphene [49,50,51]. …”

A Highly Durable, Transferable, and Substrate‐Versatile High‐Performance All‐Polymer Micro‐Supercapacitor with Plug‐and‐Play Function

“…First, complex fabrication process leads to high costs and low feasibility for scalability. [34][35][36][37][38][39] Furthermore, PPy can be synthesized by different methods under mild conditions, which vastly extends the possibility to advance the fabrication process for μSCs. Lastly, the necessity of predesign and fixed state after fabrication substantially reduces the possibility for the function of plug and play, thus not very compatible with existing electric devices.…”

“…Thus, this kind of material is urgently needed to be applied to μSCs. [34][35][36][37][38][39] Furthermore, PPy can be synthesized by different methods under mild conditions, which vastly extends the possibility to advance the fabrication process for μSCs. [28][29][30][31][32] Based on the doping and dedoping during the charging-discharging process, predoped conductive polymers show high capacitance and conductivity.…”