Enhanced electrochemical response of solution‐deposited n‐doping polymer via cocasting with ionic liquid

Abstract

A novel cocasting approach is presented for improving electroactivity of solution-cast films of conducting polymers. Solutions of the n-doping polymer poly(benzimidazobenzophenanthroline) (BBL) were co-deposited with the ionic liquid electrolyte 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide (EMIBTI). The resultant co-continuous mixture yielded highly porous polymer films (CC-BBL) upon removal of solvent and EMIBTI. Electrochemical quartz crystal microgravimetry revealed that the n-doping process in neat ionic liquid is anion-dominant, which is contrary to what is observed in dilute electrolyte solutions. The CC-BBL films exhibit a thirty-fold increase in initial current response and capacity relative to non-cocast BBL films. While current response and capacity of the non-cocast BBL improve with cycling, they level out after 800 cycles at 35% of those of the CC-BBL. CC-BBL shows high n-doping stability; no decrease in electroactivity is seen after 1000 cycles.

Dominant ion transport processes of ionic liquid electrolyte in poly(3,4‐ethylenedioxythiophene)

“…EMIBTI was prepared as reported previously 34 and purified as described elsewhere. 9,26,35 Acetonitrile was purchased from Aldrich and purified by drying over 4 Å molecular sieves followed by distillation from calcium hydride before use.…”

“…While this behavior is unusual, it is not entirely unexpected; visual observation of the direction of an actuator bending in neat ionic liquid was consistent with cationdominant transport. 18 Additionally, we have previously reported 26 that EQCM studies of an n-doping polymer in neat ionic liquid reveal anionic behavior, while cationic behavior is observed in ILE solution. Transport processes in neat ionic liquid appear to be opposite those occurring in solution-based electrolytes for both p-and n-doping polymers.…”

“…In our previous work, 26 we investigated dominant ion transport processes in the n-doping polymer poly(benzimidazobenzophenanthroline) (BBL). An increase in mass during n-doping signifies cation-dominant transport, whereas a decrease signifies anion-dominant transport.…”

Novel multi-responsive polymer materials: When ionic liquids step in

“…The electrochemical property of the MRPMs has attracted significant attention for their potential contribution in various fields owing to the tunable controls without environmental hazards [44,45]. The ionic polarization of the ILs and the mobility of the ion pairs provide electrochemical characteristics to the MRPMs [46].…”

Electroactive polymer-based electrochemical capacitors using poly(benzimidazo-benzophenanthroline) and its pyridine derivative poly(4-aza-benzimidazo-benzophenanthroline) as cathode materials with ionic liquid electrolyte

“…The electropolymerized PProDOT film was carefully blotted dry with lint free paper, and then a drop of EMIBTI was placed on top of the film. Cathodes were prepared by solution casting either BBL or Py-BBL with or without ionic liquid in methanesulfonic acid using procedures similar to what we have recently reported [18]. The asreceived BBL was dissolved at 1 wt% in methanesulfonic acid (MSA) at 80e100 C over 24e72 h. Additional samples of BBL or Py-BBL in MSA were prepared containing EMIBTI (i.e.…”