High Active Material Loading in Organic Electrodes Enabled by a Multifunctional Binder

Abstract

Organic electrodes are promising candidates for nextgeneration lithium-ion batteries due to their low cost and sustainable nature; however, they often suffer from very low conductivity and active material loadings. The conventional binder used in organic-based Li-ion batteries is poly(vinylidene fluoride) (PVDF), yet it is electrochemically inactive and thus occupies volume and mass without storing energy. Here, we report an organic mixed ionic-electronic conducting polymer, polyPEDOT-b-PEG for simplicity, as a cathode binder to address the aforementioned issues. The polymer contains a poly(3,4-ethylenedioxythiophene) (PEDOT) functionality to provide electronic conductivity, as well as poly(ethylene glycol) (PEG) chains to impart ionic conductivity to the cathode composite. We compare electrodes containing a perylene diimide (PDI) active material, conductive carbon, and a polymeric binder (either PVDF or PEDOT-b-PEG) with different weight ratios to study the impact of active material loading and type of binder on the performance of the cell. The lithium-ion cells prepared with the PEDOT-b-PEG polymer binder result in higher capacities and decreased impedance at all active material loadings compared to cathodes prepared with the PVDF-containing electrodes, demonstrating potential as a new binder to achieve higher active material loadings in organic electrodes. The strategy of preparing these polymers should be broadly applicable to other classes of mixed polymer conductors.

Influence of Backbone on the Performance of Pendant Polymer Electrode Materials in Li-ion Batteries

“…The Nyquist plots of all polymers show a characteristic high-frequency semicircle associated with charge transfer and a low-frequency Warburg tail associated with ion diffusion (Figure 5). 43 The chargetransfer resistance at the electrode/electrolyte interface (R CT ) can be found by fitting the experimental data to an equivalent circuit (more details can be found in the SI). This resistance is small for PVA and PV4VB, which show values of 40 and 19 Ω, respectively.…”

Assessing n‐type organic materials for lithium batteries: A techno‐economic review

“…For organic materials, using conductive additives with high aspect ratios such as carbon nanotubes or high surface area such as graphene, graphene oxide, and reduced graphene oxide has been reported to be an effective strategy to decrease the amount of necessary carbon in the electrode 91,137–139 . The optimization of the electrode preparation, often overlooked in fundamental studies on new materials, was also beneficial 85,128,140 …”

Sequence-Defined Conjugated Oligomers in Donor–Acceptor Dyads

“…Conjugated polymers form the basis of numerous aspects of chemical and materials research including, but not limited to, organic electronic devices, − energy storage, − fluorescent biosensors and therapeutics, − and visible-light-driven photocatalysis. , The intense interest in these materials is due, in part, to their large degree of broadly tunable electronic and physical properties. While these properties are typically dictated by the identity of the initial monomer, they may also be influenced by the chain length, monomer sequence, and side chain composition. − However, the inherent disperse nature of polymers often prevents the development of clear structure–property relationships that are needed to further elucidate fundamental processes and advance the application of these materials.…”