Binder-Free Fabrication of Nanotitania/Carbon Lithium-Ion Intercalation Electrodes

Abstract

A novel fabrication method comprising screen-printing and sintering of nanotitania/carbon paste has been developed allowing the construction of binder-free electrodes with superior lithium-ion intercalation properties. As a model active material to demonstrate the advantages of the new fabrication process, commercial P25 nanotitania product was used. The newly fabricated electrodes were compared to those fabricated using the standard binder-based method. Physical characterization demonstrated that the novel binder-free paste provides for significant carbon dispersion due to smaller agglomerate size resulting in enhanced inter-particle (active-conducting) mixing and packing density than the standard one. Cyclic voltammetry and galvanostatic charge/discharge testing proved the novel method-built electrodes to exhibit dramatically improved performance over the standard electrode in terms of conductivity, specific charge capacity, and reversibility. Thus the specific charging (delithiation) capacity of the novel method electrode (92% TiO2/7.5% C) was 174 mA h g−1, compared to 124 mA h g−1 for the standard method electrode (85% TiO2/7.5% C/7.5% PVDF), representing 103, and 74% of the theoretical capacity (corresponding to Li0.5TiO2), respectively. At the same time after 10 cycles, the novel-built electrode exhibited 90–94% coulombic efficiency and more than 92% capacity retention while the corresponding values for the standard electrode were only 80–82% and 53% respectively.