Multifunctional SA-PProDOT Binder for Lithium Ion Batteries

Abstract

An environmentally benign, highly conductive, and mechanically strong binder system can overcome the dilemma of low conductivity and insufficient mechanical stability of the electrodes to achieve high performance lithium ion batteries (LIBs) at a low cost and in a sustainable way. In this work, the naturally occurring binder sodium alginate (SA) is functionalized with 3,4-propylenedioxythiophene-2,5-dicarboxylic acid (ProDOT) via a one-step esterification reaction in a cyclohexane/dodecyl benzenesulfonic acid (DBSA)/water microemulsion system, resulting in a multifunctional polymer binder, that is, SA-PProDOT. With the synergetic effects of the functional groups (e.g., carboxyl, hydroxyl, and ester groups), the resultant SA-PProDOT polymer not only maintains the outstanding binding capabilities of sodium alginate but also enhances the mechanical integrity and lithium ion diffusion coefficient in the LiFePO4 (LFP) electrode during the operation of the batteries. Because of the conjugated network of the PProDOT and the lithium doping under the battery environment, the SA-PProDOT becomes conductive and matches the conductivity needed for LiFePO4 LIBs. Without the need of conductive additives such as carbon black, the resultant batteries have achieved the theoretical specific capacity of LiFePO4 cathode (ca. 170 mAh/g) at C/10 and ca. 120 mAh/g at 1C for more than 400 cycles.

Trifunctional Electrode Additive for High Active Material Content and Volumetric Lithium‐Ion Electrode Densities

“…In addition, high resolution X-ray photoelectron spectroscopy (XPS) spectrum of C 1s shows main peak centres at 284.8 and 285.8 eV ( Figure S2, Supporting Information), corresponding to CC and CO groups, respectively. [19,20] Furthermore, the calculated band structure demonstrates that the lowest unoccupied molecular orbital (LUMO) (blue line) of Li-doped PFA is lower than Lidoped polyvinylidene fluoride (PVDF, Figure 1d). Synchrotron-based X-ray absorption spectroscopy (sXAS) was used to assess excitations of core level electrons to unoccupied states of the PFA.…”

“…[1,2] Be it consumer electronics or electric vehicles, the size of the battery and the corresponding amount of deliverable energy and power strongly influences their commercial competitiveness. While there has been some works on dual-function conductive binder, [16][17][18][19][20][21][22][23] these binders have not been accepted into the industry likely due to complicated, toxic, and expensive synthesis methods that are required. As such, the electrode density and volumetric energy density of typical commercial LFP electrodes are only ≈2.0 g cm −3 and ≈1100 Wh L −1 , respectively, indicating much room for improvement.…”

Investigation on xanthan gum as novel water soluble binder for LiFePO 4 cathode in lithium-ion batteries

“…Among various aqueous polymeric binder demonstrated so far, polyacrylic acid (PAA) and its neutralized salts (PAALi, PAANa and PAAK) [5][6][7][8], chitosan and its derivatives (CTS, CCTS and CN-CCTS) [9][10][11], lithium or sodium salts of carboxymethyl cellulose (CMCLi, CMCNa) and its composite binder (CMC-PEDOT:PSS) [12,13], styrene-butadiene rubber (SBR) [7], poly vinyl acetate (PVAc) [14] and polytetrafluoroethylene (PTFE) [15] have been employed and studied for LFP cathode, which are superior to the conventional PVDF in battery performances such as either promoting the cycle stability or enhancing the rate capability. Besides the water-soluble binders mentioned above, some NMP-based binders such as polyaniline (PANI) [16], poly(methyl methacrylate) (PMMA) [17], poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) [18], and sodium alginate functionalized with 3,4-propylenedioxythiophene-2,5-discarboxylic acid (SA-PProDOT) [19] for LFP cathode were also investigated. Apart from the above binders for LFP cathode, various novel binders including pectin [20], lignin [21], hyperbranched β-cyclodextrin…”

A New Type of Multifunctional Polar Binder: Toward Practical Application of High Energy Lithium Sulfur Batteries

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The binder is an important ingredient in battery functions to bond and keep the active materials in the electrode, which helps to improve electrical contact between the active materials and conductive carbon as well as to link the active materials with the current collector. [24][25][26][27][28] For example, polyvinylidene fluoride (PVDF) is typically used as a conventional binder for Li-S batteries. [24][25][26][27][28] For example, polyvinylidene fluoride (PVDF) is typically used as a conventional binder for Li-S batteries.

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