Conducting Polymer-Skinned Electroactive Materials of Lithium-Ion Batteries: Ready for Monocomponent Electrodes without Additional Binders and Conductive Agents

Abstract

Rapid growth of mobile and even wearable electronics is in pursuit of high-energy-density lithium-ion batteries. One simple and facile way to achieve this goal is the elimination of nonelectroactive components of electrodes such as binders and conductive agents. Here, we present a new concept of monocomponent electrodes comprising solely electroactive materials that are wrapped with an insignificant amount (less than 0.4 wt %) of conducting polymer (PEDOT:PSS or poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate)). The PEDOT:PSS as an ultraskinny surface layer on electroactive materials (LiCoO2 (LCO) powders are chosen as a model system to explore feasibility of this new concept) successfully acts as a kind of binder as well as mixed (both electrically and ionically) conductive film, playing a key role in enabling the monocomponent electrode. The electric conductivity of the monocomponent LCO cathode is controlled by simply varying the PSS content and also the structural conformation (benzoid-favoring coil structure and quinoid-favoring linear or extended coil structure) of PEDOT in the PEDOT:PSS skin. Notably, a substantial increase in the mass-loading density of the LCO cathode is realized with the PEDOT:PSS skin without sacrificing electronic/ionic transport pathways. We envisage that the PEDOT:PSS-skinned electrode strategy opens a scalable and versatile route for making practically meaningful binder-/conductive agent-free (monocomponent) electrodes.

Interface modification in high voltage spinel lithium-ion battery by using N-methylpyrrole as an electrolyte additive

“…Conducting polymer coating is also reported as another strategy, which not only be able to protect the surface of cathode, but also to serve as a conductive matrix. Compounds such as aniline [17,18], pyrrole [19,20], 3,4-ethylenedioxythiophene [21,22], acrylonitrile [23] [24]. Employing monomer units of conducting polymers as electrolyte additives is a more economic and effective way to in-situ coat the electrode [25][26][27].…”

New functional conducting poly-3,4-ethylenedioxythiopene:polystyrene sulfonate/carboxymethylcellulose binder for improvement of capacity of LiFePO4-based cathode materials

“…Additional improvement of the electrochemical properties of LFP-based cathode materials with the use of conducting polymer coatings [9][10][11][12][13][14][15][16][17][18][19][20], and in particular, poly-3,4-ethylenedioxythiopene [12,[13][14][15] was proposed.…”

Electroconducting materials based on polypyrrole

“…Very high specific capacitance and good high-rate capability of electrode material has been achieved by synthesis of PPy/CNT composite with controlled pore size in a three-dimensional entangled structure of a CNT film using an electrostatic spray deposition process [112]. Recently, Paul et al synthesized polypyrrole (PPy) / multi-walled carbon nanotube (MWCNT) / conductive carbon (CC) composites by chemical oxidative polymerization method using anhydrous FeCl 3 . The impedance behavior of PPy / MWCNT / CC electrodes in their insulating state, have been taken before and after performed chargingdischarging 500 cycles in the potential range from 0 to 0.6 V. Charge transfer resistance, R ct , of composites comprising 10, 15 and 20 wt% of MWCNT determined before cycling processes have shown values of 7.4, 2.1 and 4.3 respectively, which indicated that only optimal amount of MWCNT could facilitate the charge transfer throughout the system [113].…”

“…One of the most interesting materials of this kind are electroconducting polymer materials (ECP) regarding the possibility of reversible change of their reduced (insulating) and oxidized (conducting) state by the means of the processes of reduction (undoping) and oxidation (doping). This feature, offers very broad application areas of electroconducting polymer materials, as electrodes in rechargeable batteries [1], electrochemical capacitors (supercapacitors) [2,3], sensors [4], actuators [5], solar cells [6], selective gas membranes [7], in the corrosion protection [8,9], and even in the field of drug delivery [10] and tissue engineering systems [11]. The interest for electroconducting materials (ECM) in general started back in the '70s of the last century by the discovery of changes in the electroconducting properties of polyacetylene, firstly synthesized in 1958, by its treatment with oxidizing agent, e.g.…”