Effects of the Solvent Concentration (Solid Loading) on the Processing and Properties of the Composite Electrode

Abstract

For various composite electrodes with the same composition 80͑73 wt % Li 1.1 V 3 O 8 , 8 wt % CB, 19 wt % PMMA͒-20͑EC-PC͒, and made by the solvent casting technique, the cycled capacity varies between 100 and 250 mAh/g depending on the initial volatile solvent concentration. For a concentration below the optimal one, the electrode dispersion exhibits a yield stress that inhibits flow and prevents homogeneous distribution of the constituents. Above the optimal concentration, settling of the particles in the low viscosity dispersion can create a concentration gradient. Below and above the optimal solvent concentration, the electrochemical performance is degraded due to poor electronic wiring of the active material. A generalization of this work to other materials and composite electrode formulations is discussed. In particular, satisfactory prediction of settling rate has been achieved using relations derived from Stokes' law and material parameters.

Influence of Electrode Density on the Performance of Li-Ion Batteries: Experimental and Simulation Results

“…Thus, the solvent concentration (or solid loading) has a strong impact on the morphology and consequently on the electrochemical performance of the CE. Below and above the optimal solvent concentration, the electrochemical behavior is degraded due to poor electronic wiring of the AM [18].…”

A Multiscale Description of the Electronic Transport within the Hierarchical Architecture of a Composite Electrode for Lithium Batteries

“…[31] The yield stress is the manifestation of a sample-spanning network of agglomerates interconnected throughout the system. [45] The evolution of the yield stress t 0 with the volume fraction f of solid particles (Li 1.1 V 3 O 8 or CB) is given for electrode slurries and model Li 1.1 V 3 O 8 þ PMMA and CB þ PMMA dispersions, all with EC þ PC added, in Figure 2b.…”

“…The composite electrodes studied here were thoroughly characterized in our previous work. [13,15,[30][31][32][33][34][35] They are based on the lithium trivanadate (Li 1.1 V 3 O 8 ) active material, which offers a high theoretical capacity of 330 mA h g À1 and has been investigated as a promising positive electrode AM. [36][37][38][39] Various composite electrodes have been prepared in which the surrounding of the same Li 1.1 V 3 O 8 is changed by pre-plasticizing the poly(methylmethacrylate) (PMMA) binder with ethylene carbonate (EC) and propylene carbonate (PC).…”

Engineering advanced Li1.2V3O8 composite electrodes for lithium batteries

“…the electrochemistry and the solid/liquid dispersions and the polymer sciences. Results from Guy et al [2,3] and Ligneel et al [4,5] are a striking example demonstrating that the electrochemical performance of the composite electrode may strongly depend on the composite electrode engineering. A 50% increase in the cycling capacity of Li 1.2 V 3 O 8 -based electrodes was obtained after using a pre-plasticization of the poly (ethylene oxide) (PEO) or poly(methyl methacrylate) (PMMA) B by the solvent (ethylene carbonate [EC]+ propylene carbonate [PC]) of the liquid electrolyte and by adjusting the volatile solvent concentration.…”

“…However, in the abovementioned studies, the electrode processing conditions involved toxic solvents such as acrylonitrile (AN) or tetrahydrofuran (THF) and the magnetic stirrer as a "laboratory" dispersing tool [2][3][4][5]. The extrapolation to industry would therefore require the usage of a more environmentally friendly solvent and a dispersing device adapted to large-scale production.…”