Lignin as a Binder Material for Eco-Friendly Li-Ion Batteries

Abstract

The industrial lignin used here is a byproduct from Kraft pulp mills, extracted from black liquor. Since lignin is inexpensive, abundant and renewable, its utilization has attracted more and more attention. In this work, lignin was used for the first time as binder material for LiFePO4 positive and graphite negative electrodes in Li-ion batteries. A procedure for pretreatment of lignin, where low-molecular fractions were removed by leaching, was necessary to obtain good battery performance. The lignin was analyzed for molecular mass distribution and thermal behavior prior to and after the pretreatment. Electrodes containing active material, conductive particles and lignin were cast on metal foils, acting as current collectors and characterized using scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge cycles. Good reversible capacities were obtained, 148 mAh·g−1 for the positive electrode and 305 mAh·g−1 for the negative electrode. Fairly good rate capabilities were found for both the positive electrode with 117 mAh·g−1 and the negative electrode with 160 mAh·g−1 at 1C. Low ohmic resistance also indicated good binder functionality. The results show that lignin is a promising candidate as binder material for electrodes in eco-friendly Li-ion batteries.

Sustainable Battery Materials from Biomass

“…The extraction method and hence the exact structure and functionalities of lignin have only minor influences here. In contrast, the molecular weight matters, and low molecular weight fractions need to be removed for good binder behavior …”

Lignin‐derived electrochemical energy materials and systems

“…Lignin‐based binders can be promising substitutes because of their environmental friendliness and low cost. For example, both LiFePO 4 and graphite electrodes with lignin binders exhibited better performance than electrodes with traditional binders . As shown in Fig.…”

More sustainable energy storage: lignin based electrodes with glyoxal crosslinking

“…1,2 Depolymerization approaches to gain low molecular weight fuels or functional chemicals 3,4 as well as approaches for the synthesis of higher molecular weight value-added materials from lignin, 5 e.g., adhesives, [6][7][8] or even energy storage materials have been presented. [9][10][11][12] In the latter research area, the tremendous demand for more, better (high charge and high power), smaller (or bigger) charge storage devices, e.g., in consumer electronics, electromobility, or grid storage, has led to skyrocketing production of batteries. This inherently results in a massive environmental impact during mining and device fabrication also leads to eerie amounts of hazardous waste once the devices are sorted out.…”

“…On the other hand, using lignin as a binder to limit the use of uorinated polymer binders like polytetra-uoroethylene (PTFE) or polyvinylidene uoride (PVDF) was only successful in thin electrodes with a signicant amount of polyethylene glycol addition to counteract decreasing mechanical stability. 9 For avoiding unsustainable conductive polymer additives, we previously discussed composite electrodes of lignin and conductive high surface area carbons, in which the latter were derived from renewable resources. 16 Good contact, necessary for high electroactivity, can best be achieved using low molecular weight polymers.…”