Aqueous and organic inks of carbon xerogels as models for studying the role of porosity in lithium-ion battery electrodes

Abstract

The electrochemical performances of lithium-ion batteries depend to a great extent on the method used to prepare the electrodes and on the pore texture of the active material. In the present study, carbon xerogels with different pore sizes and pore volumes were synthesized by means of microwave heating. These carbonaceous materials were used to prepare lithium-ion battery anodes. Generally, electrodes are prepared by coating a slurry made of an active material, a binder and N-methyl-2-pyrrolidone as organic solvent. The disadvantage of this solvent is that it is both toxic and costly. In this work, the use of water instead of the organic solvent and water-soluble binders yielded electrodes with similar electrochemical performances making the battery assembly process more economic and environmentally friendly. The results of this study also confirm that the use of an aqueous preparation pathway does not undermine the interdependence between the electrochemical properties of the cells and the porous properties of the carbon xerogels.

Graphitized Carbon Xerogels for Lithium-Ion Batteries

“…The operating mechanism of lithium-ion batteries is based on the transformation of chemical energy into electrical energy [3,4], and are composed by electrochemical units known as cells. Each cell is made up of two electrodes separated by a porous fiberglass and submerged in an electrolyte [3,5,6].…”

“…The operating mechanism of lithium-ion batteries is based on the transformation of chemical energy into electrical energy [3,4], and are composed by electrochemical units known as cells. Each cell is made up of two electrodes separated by a porous fiberglass and submerged in an electrolyte [3,5,6]. The electrolytes employed are commonly composed of lithium salts dissolved in an organic solvent, while the cathode and the anode are made up of different transition metals-lithium oxides, and carbonaceous materials, respectively [4,[7][8][9].…”

“…For the anode, graphite is the carbon most commonly used as active material in commercial LIBs since it is easily accessible, cheap, and offers operational advantages over other non-carbon materials [1,12]. However, its maximum specific capacity is limited to 372 mAh g −1 (1 lithium atom per 6 carbon atoms) and its structure is prone to irreversible expansion due to the continuous insertion-release of ions, which causes degradation of the electrode and therefore short durability of the cell [3,4,11,13]. For this reason, other carbonaceous materials, including carbon nanotubes, carbon nanofibers or graphene, appear as possible substitutes for graphite [1,14,15].…”

Water‐Based Paintable LiCoO2Microelectrodes: A High‐Rate Li‐Ion Battery Free of Conductive and Binder Additives

“…Therefore, the use of water and other nontoxic solvents has been amply suggested . This, however, implies a change of the BA toward water‐soluble binders and/or dispersants, such as styrene–butadiene rubber, sodium carboxymethyl cellulose, phenolic compounds, poly(4‐styrene sulfonic acid), poly(ethyleneimine), or poly(acrylamide‐ co ‐diallyldimethylammonium chloride) . Léonard and Job used xanthan gum as common binder to obtain water‐based slurries for the assembly of safe and green Li‐ion batteries based on LiFePO 4 and Li 4 Ti 5 O 12 .…”

Acid-based resorcinol-formaldehyde xerogels synthesized by microwave heating

“…Resorcinol-formaldehyde (RF) gels are porous materials obtained by means of a polymerization reaction [1][2][3]. These materials have aroused widespread interest among the scientific community over the past two decades due to their excellent properties and diverse applications [4][5][6][7][8]3]. Some of the most notable features of these materials include their high purity, low density, controllable porous structure and the possibility of doping them with metals or other substances [8][9][10]6].…”