Mixed Ionic–Electronic Conduction Increases the Rate Capability of Polynaphthalenediimide for Energy Storage

Abstract

Conjugated polymers offer a number of unique and useful properties for use as battery electrodes, and recent work has reported that conjugated polymers can exhibit excellent rate performance due to electron transport along the polymer backbone. However, the rate performance depends on both ion and electron conduction, and strategies for increasing the intrinsic ionic conductivities of conjugated polymer electrodes are lacking. Here, we investigate a series of conjugated polynapthalene dicarboximide (PNDI) polymers containing oligo(ethylene glycol) (EG) side chains that enhance ion transport. We produced PNDI polymers with varying contents of alkylated and glycolated side chains and investigated the impact on rate performance, specific capacity, cycling stability, and electrochemical properties through a series of charge−discharge, electrochemical impedance spectroscopy, and cyclic voltammetry measurements. We find that the incorporation of glycolated side chains results in electrode materials with exceptional rate performance (up to 500C, 14.4 s per cycle) in thick (up to 20 μm), high-polymer-content (up to 80 wt %) electrodes. Incorporation of EG side chains enhances both ionic and electronic conductivities, and we found that PNDI polymers with at least 90% of NDI units containing EG side chains functioned as carbon-free polymer electrodes. This work demonstrates that polymers with mixed ionic and electronic conduction are excellent candidates for battery electrodes with good cycling stability and capable of ultra-fast rate performance.

Fabrication of highly stretchable salt and solvent blended PEDOT:PSS/PVA free-standing films: non-linear to linear electrical conduction response

“…The dissociation of inorganic salt in polymer system becomes more feasible through the reduction of lattice energy of salt and elevating the dielectric constant of the polymer. 75,76,[78][79][80] Here, aer incorporation of salts, it is obvious from XRD that polymeric regions of PVA transform from semicrystalline to almost amorphous nature, whereas PSS regions remain in amorphous state and therefore, the prepared polymeric lms show exibility. Thus, segmental motion is occurred inside polymer chains.…”

From Nature to Technology: Exploring the Potential of Plant-Based Materials and Modified Plants in Biomimetics, Bionics, and Green Innovations

“…Specifically, devices using organic electronic materials as active layers have the benefit of signal transduction. This is because they combine ionic and electronic conduction, allowing for close interaction with the naturally ionic biological environment [216].…”

Pseudocapacitive gels based on conjugated polyelectrolytes: thickness and ion diffusion limitations

“…[11][12][13][14][15][16] However, optimizing ionic conductivity and electrolyte accessibility in CP-based pseudocapacitors is still needed to maximize pseudocapacitance. 6,[17][18][19] Conductive polymer hydrogels (CPHs) are gaining interest as pseudocapacitive electrode materials due to specic physicoelectrochemical properties that are difficult to achieve with traditional CP thin lms. 9 In particular, CPHs can exhibit a large EASA when an interconnected morphology is present, leading to useful ionic and electrical conductivities and competitive capacitance per unit of area of the charge-collecting working electrode (areal capacitance, C Areal ).…”

“…11–16 However, optimizing ionic conductivity and electrolyte accessibility in CP-based pseudocapacitors is still needed to maximize pseudocapacitance. 6,17–19…”