Thermally doped polypyrrole nanotubes with sulfuric acid for flexible all-solid-state supercapacitors

Abstract

We have synthesized a binder-free electrode on the basis of thermal acid doped polypyrrole nanotubes on carbon cloth (CC/PPy NTs-T), which can be used for flexible all-solid-state supercapacitors (FSSCs). PPy NTs on the CC substrate (CC/PPy NTs) with an interconnected network structure were prepared by a facile self-degradation template method. Then a unique acid doping process at high temperature was developed and used to fabricate the CC/PPy NTs-T composite electrodes, showing the better electrochemical performances than the CC/PPy NTs (without doping) and CC/PPy NTs-R (doping at room temperature) composite electrodes. The CC/PPy NTs-T FSSCs were assembled based on the prepared CC/PPy NTs-T composite electrodes, which showed good flexibility and excellent electrochemical performances with a high areal specific capacitance of 73.3 mF cm −2 at the current density of 1 mA cm −2 , the highest energy density of 0.081 mW h cm −3 , the highest power density of 25 mW cm −3 , and the capacitance retention of 85.3% after 5000 cycles. The outstanding electrochemical performances can be attributed to the unique interconnected network structure of the composite electrodes and the thermal acid doping of PPy NTs, which proposes a new and feasible general pathway of flexible electrode configuration for energy storage devices.

Vertically Aligned Conductive Polymeric Nanotubes Grown on Percolated Multiwalled Carbon Nanotube Films for Supercapacitor Electrodes

“…The presence of the PETE membrane in the electrochemical measurements ensures the nanotubes keep vertically aligned, preventing nanotubes pairing and allowing the electrolyte to reach the inner space of the hollow nanotubes. The electrodes that contain nonaligned nanotubes in contact with an electrolytic solution generally present low ionic migration and make it difficult for ions to access the electrode, which is not desirable for energy storage applications …”

“…The electrodes that contain nonaligned nanotubes in contact with an electrolytic solution generally present low ionic migration make it difficult for ions to access the electrode, which is not desirable for energy storage applications. 43 Cyclic voltammetry (CV) curves at scan rates from 10 to 200 mV/s were recorded (Figure 5a). The curves showed good capacitive behavior, and the quasi-rectangular shape of the voltammograms and the presence of anodic and cathodic peaks indicated the contribution of both electric double-layer capacitance (EDLC) and pseudocapacitive phenomena.…”

Ag(e)ing and Degradation of Supercapacitors: Causes, Mechanisms, Models and Countermeasures

“…This concern also applies to changes of precursors in other synthetic procedures [ 38 ]. During synthetic procedures, templates may be used (see, e.g., [ 39 , 40 , 41 ]). When they are removed later in the synthetic procedure, this may be termed degradation (of the template).…”