Design and evaluation of conjugated polymers with polar side chains as electrode materials for electrochemical energy storage in aqueous electrolytes

Moia, Davide; Giovannitti, Alexander; Szumska, Anna A.; Maria, Iuliana P.; Rezasoltani, Elham; Sachs, Michael L.; Schnurr, Martin; Barnes, Piers R. F.; McCulloch, Iain; Nelson, Jenny

doi:10.1039/c8ee03518k

Cited by 170 publications

(257 citation statements)

References 43 publications

Supporting

Mentioning

253

Contrasting

Order By: Relevance

“…A swollen film is known to facilitate ion motion, but, as shown in Figure , this is not a requirement for high capacitance or swelling is not de facto beneficial for OECT performance. The volumetric capacitance might decrease due to the increased film volume, and increased fraction of EG side chains which dilutes the electronic content. Proctor et al describes capacitance in terms of “sites” in which ions injected from the electrolyte compensate for the electronic charges that are injected to the film by a metal contact .…”

Section: Resultsmentioning

confidence: 99%

Balancing Ionic and Electronic Conduction for High‐Performance Organic Electrochemical Transistors

Savva

Hallani

Cendra

et al. 2020

Adv Funct Materials

Self Cite

164

239

View full text Add to dashboard Cite

Conjugated polymers that support mixed (electronic and ionic) conduction are in demand for applications spanning from bioelectronics to energy harvesting and storage. To design polymer mixed conductors for high‐performance electrochemical devices, relationships between the chemical structure, charge transport, and morphology must be established. A polymer series bearing the same p‐type conjugated backbone with increasing percentage of hydrophilic, ethylene glycol side chains is synthesized, and their performance in aqueous electrolyte gated organic electrochemical transistors (OECTs) is studied. By using device physics principles and electrochemical analyses, a direct relationship is found between the OECT performance and the balanced mixed conduction. While hydrophilic side chains are required to facilitate ion transport—thus enabling OECT operation—swelling of the polymer is not de facto beneficial for balancing mixed conduction. It is shown that heterogeneous water uptake disrupts the electronic conductivity of the film, leading to OECTs with lower transconductance and slower response times. The combination of in situ electrochemical and structural techniques shown here contributes to the establishment of the structure–property relations necessary to improve the performance of polymer mixed conductors and subsequently of OECTs.

show abstract

Section: Resultsmentioning

confidence: 99%

Balancing Ionic and Electronic Conduction for High‐Performance Organic Electrochemical Transistors

Savva

Hallani

Cendra

et al. 2020

Adv Funct Materials

Self Cite

164

239

View full text Add to dashboard Cite

show abstract

“…We choose n i = 6 to be the highest reversible oxidation state of p(gT2) based on density functional theory (DFT) calculations. [6] As the polymer chains oxidize, they become more loosely packed and the film swells due to inclusion of ions, water and reorganization of the polymer chains, as illustrated by snapshots in Figure 3d-g (second column). At the neutral state, n i = 0, no swelling of the polymer film is observed, with basically no water molecules entering the film, but rather with water surrounding the side chains that are located along the outer surface.…”

Section: Doi: 101002/advs201901144mentioning

confidence: 99%

“…Recently, the engineering of hydrophilicity in conjugated polymers backbone has received significant attention as improved ion transport can enhance the performance in electrochemical devices for medical and energy storage applications. [6,7] In particular, ethylene glycol based side chains have been identified to enhance the transport of hydrated anions [7][8][9] since those molecular moieties can strongly interact with water to promote swelling of the resulting polymer. [8,10] In these systems the initial hydration depends on the glycol chains content, [8] morphology, [9] and type of electrolyte [10] while the swelling during electrochemical cycling has not been studied extensively.…”

Section: Doi: 101002/advs201901144mentioning

confidence: 99%

“…Repeated doping and de-doping at ±0.8 V, versus the counter electrode, is at the limit of the polymer's electrochemical window ( Figure S4, Supporting Information) and results in partial degradation of the polymer due to overoxidation and possibly also due to lower mechanical integrity. [6] This very large but irreversible volumetric switching that occurs during its first oxidation process suggests that the ±0.8 V region can be explored in, for example, single-switch electro-valve applications.…”

Section: Doi: 101002/advs201901144mentioning

confidence: 99%

See 1 more Smart Citation

Reversible Electronic Solid–Gel Switching of a Conjugated Polymer

et al. 2019

Self Cite

View full text Add to dashboard Cite

Conjugated polymers exhibit electrically driven volume changes when included in electrochemical devices via the exchange of ions and solvent. So far, this volumetric change is limited to 40% and 100% for reversible and irreversible systems, respectively, thus restricting potential applications of this technology. A conjugated polymer that reversibly expands by about 300% upon addressing, relative to its previous contracted state, while the first irreversible actuation can achieve values ranging from 1000–10 000%, depending on the voltage applied is reported. From experimental and theoretical studies, it is found that this large and reversible volumetric switching is due to reorganization of the polymer during swelling as it transforms between a solid‐state phase and a gel, while maintaining percolation for conductivity. The polymer is utilized as an electroactive cladding to reduce the void sizes of a porous carbon filter electrode by 85%.

show abstract

“…[21,41] However, these techniques only stabilize the channel for a relatively low conductance range (≈1.2 × conductance modulation), whereas a broader conductance range (≈2×) is desired for ANN applications. Furthermore, the reported strategies are expected to be applicable for a broad range of organic electrochemical devices, notably charge storage devices including organic supercapacitors [43] and batteries, [44,45] as well as organic electrochemical transistors (OECTs). In this work, we elucidate the physical and chemical mechanisms leading to resistance state decay and cycling instability in PEDOT/PEI:PSS ENODes and demonstrate methods to mitigate these effects, such as amine vapor doping and the use of a diffusion barrier.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms for Enhanced State Retention and Stability in Redox‐Gated Organic Neuromorphic Devices

Keene

Melianas

Burgt

et al. 2018

Adv Elect Materials

View full text Add to dashboard Cite

units (GPUs) and >1000 central processing units (CPUs) for some of the highest performance demonstrations. [4] In order to approach the massively parallel and energy efficient operation of the brain (≈25 W), [7] neuromorphic computing architectures have been proposed which utilize physical processes in materials to emulate synaptic behavior. [8][9][10] Among these, resistive memory (memristive) devices [11,12] have gained traction as a highly suitable option, offering projected efficiency gains of up to 10 6 over von Neumann architectures when implementing ANN algorithms. [13,14] Efficiency gains originate from parallel computation and scale with array size (N) [15] : an N × N sized neuromorphic array can simultaneously perform N 2 operations using Ohm's and Kirchoff's laws (multiply and accumulate, respectively), whereas GPUs can perform only N operations simultaneously.Nonvolatile memristive devices such as phase change memory (PCM) and resistive random-access memory (ReRAM) have been proposed for use as nonvolatile artificial synapses due to their ability to tune the resistance state by applied voltage pulses. [16][17][18] By arranging these devices in a crossbar array architecture, vector-matrix multiplication (VMM) can be performed in an analog fashion where the input vector is represented by voltages, the operator matrix is represented by the conductance of each memristive element, and the output vector is represented by currents. These crossbar arrays have recently been implemented in a dot-product engine which uses VMM operations to classify handwritten digits with ≈90% accuracy. [19] However, this demonstration requires a timeconsuming feedback programming scheme which reduces the parallelism of the write operation to the array and ultimately its overall efficiency.Recently, electrochemical nonvolatile redox memory (NVRM) devices [20,21] have emerged as an ideal candidate for neuromorphic arrays as they decouple read and write operations, thereby allowing for low-energy programming and accurately tunable conductance states while potentially avoiding the time-voltage dilemma. [22,23] Furthermore, organic materials are an attractive alternative to conventional resistive memory due to their linearly tunable conductance, [22] biocompatibility, [24] and unique switching mechanisms which significantly differ from their inorganic counterparts. [25][26][27][28][29][30] In particular, there has been interest in mixed ionic-electronic conductors, Recent breakthroughs in artificial neural networks (ANNs) have spurred interest in efficient computational paradigms where the energy and time costs for training and inference are reduced. One promising contender for efficient ANN implementation is crossbar arrays of resistive memory elements that emulate the synaptic strength between neurons within the ANN. Organic nonvolatile redox memory has recently been demonstrated as a promising device for neuromorphic computing, offering a continuous range of linearly programmable resistance states and tunable electronic and elect...

show abstract

Design and evaluation of conjugated polymers with polar side chains as electrode materials for electrochemical energy storage in aqueous electrolytes

Abstract: Solution processable p-type and n-type conjugated polymers with polar side chains enable fast charging in aqueous electrolytes and 1.4 V cell voltage.

Cited by 170 publications

References 43 publications

Balancing Ionic and Electronic Conduction for High‐Performance Organic Electrochemical Transistors

Balancing Ionic and Electronic Conduction for High‐Performance Organic Electrochemical Transistors

Reversible Electronic Solid–Gel Switching of a Conjugated Polymer

Mechanisms for Enhanced State Retention and Stability in Redox‐Gated Organic Neuromorphic Devices

Contact Info

Product

Resources

About