Flexible Overoxidized Polypyrrole Films with Orderly Structure as High-Performance Anodes for Li- and Na-Ion Batteries

Abstract

Flexible polypyrrole (PPy) films with highly ordered structures were fabricated by a novel vapor phase polymerization (VPP) process and used as the anode material in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). The PPy films demonstrate excellent rate performance and cycling stability. At a charge/discharge rate of 1 C, the reversible capacities of the PPy film anode reach 284.9 and 177.4 mAh g in LIBs and SIBs, respectively. Even at a charge/discharge rate of 20 C, the reversible capacity of the PPy film anode retains 54.0% and 52.9% of the capacity of 1 C in LIBs and SIBs, respectively. After 1000 electrochemical cycles at a rate of 10 C, there is no obvious capacity fading. The molecular structure and electrochemical behaviors of Li- and Na-ion doping and dedoping in the PPy films are investigated by XPS and ex situ XRD. It is believed that the PPy film electrodes in the overoxidized state can be reversibly charged and discharged through the doping and dedoping of lithium or sodium ions. Because of the self-adaptation of the doped ions, the ordered pyrrolic chain structure can realize a fast charge/discharge process. This result may substantially contribute to the progress of research into flexible polymer electrodes in various types of batteries.

Conjugated Microporous Polytetra(2‐Thienyl)ethylene as High Performance Anode Material for Lithium‐ and Sodium‐Ion Batteries

“…The low initial Coulombic efficiency can be attributed to irreversible reaction, which is a common phenomenon of anode materials for LIBs and could be mitigated by some prelithiation processes . Figure c shows the rate performance of PTTE‐based LIBs, PTTE can deliver specific capacitance of 973 mA h g −1 at a current density of 100 mA g −1 , which is much higher than that of most reported organic anode materials, such as Li 4 C 8 H 4 O 4 nanosheets (232 mA h g −1 at 24.1 mA g −1 ), CMP from porphyrin with 4‐thiophenephenyl groups (TThPP) (666 mA h g −1 at 200 mA g −1 ), poly(bithiophene)/carbon (PBT/C) composite (650 mA h g −1 at 320 mA g −1 ), PDCzBT (404 mA h g −1 at 100 mA g −1 ) and the ordered polypyrrole film (285 mA h g −1 at 300 mA g −1 ) . The high specific capacity of PTTE might be attributed to its high surface area and inherent homogeneous microporous structure, endowing PTTE with abundant active sites for Li ion storage.…”

“…[49,50] Figure 2c shows the rate performance of PTTE-based LIBs, PTTE can deliver specific capacitance of 973 mA h g −1 at a current density of 100 mA g −1 , which is much higher than that of most reported organic anode materials, such as Li 4 C 8 H 4 O 4 nanosheets (232 mA h g −1 at 24.1 mA g −1 ), [47] CMP from porphyrin with 4-thiophenephenyl groups (TThPP) (666 mA h g −1 at 200 mA g −1 ), [51] poly(bithiophene)/carbon (PBT/C) composite (650 mA h g −1 at 320 mA g −1 ), [52] PDCzBT (404 mA h g −1 at 100 mA g −1 ) [27] and the ordered polypyrrole film (285 mA h g −1 at 300 mA g −1 ). [53] The high specific capacity of PTTE might be attributed to its high surface area and inherent homogeneous microporous structure, endowing PTTE with abundant active sites for Li ion storage. In addition, PTTE shows a low the lowest unoccupied molecular orbital level of −3.59 eV ( Figure S4, Supporting Information), which facilitates the electron injection into the polymer chains, [54,55] leading to a complete lithiation reaction to thiophene units of PTTE.…”

Recent advances on flexible electrodes for Na-ion batteries and Li–S batteries

“…(h) SEM micrograph of CuO nanorod array on Cu foil [133] . (i) Schematic illustration of Na-ions storage mechanism in polypyrrole film [127] .…”

“…Polymeric film can be used as a promising flexible anode material for SIB. Yuan et al [127] have demonstrated polypyrrole film as a potential flexible anode material for SIB. It was prepared via vapor phase polymerization method (Table S1aj) bonds.…”

A Functionally Graded Cathode Architecture for Extending the Cycle‐Life of Potassium‐Oxygen Batteries

“…In this article, polypyrrole is chosen for the inner layer due to its facile and scalable synthesis, electric conductivity, low gas permeability and support for ORR/OER. [16,17,18,19,20] It should be noted that PPy-based membranes have been applied in Li-air batteries by Cui et al to promote oxygen diffusion into the cathode on the air side using a tubular architecture. [21] PPy/ carbon nanocomposite has been applied as a cathode in a hybrid Li-air battery, and it has been clearly demonstrated to support ORR with sufficiently high electrocatalytic activity.…”