Influence of Li concentration on structural, morphological and electrochemical properties of anatase-TiO₂...

Lithium-doped anatase-TiO₂ nanoparticles (Li_xTi_1-xO₂ NPs, x = 0, 0.05, 0.10, 0.15 and 0.20) could be synthesized by a simple sol-gel process. X-ray diffraction (XRD) results displayed the tetragonal (space group: I41/amd) of polycrystalline TiO₂ anatase phase. The spectroscopy results of Raman and FT-IR confirmed the anatase phase of TiO₂ through the specific modes of metal oxides vibration in the crystalline TiO₂. Surfaces micrographs by scanning electron microscope (SEM) of agglomerated Li_xTi_1-xO₂ NPs showed a spongy like morphology. Transmission electron microscope (TEM) illustrated a cuboidal shape of dispersed NPs with particle size distributed in a narrow range 5-10 nm. Bruanauer Emmett-Teller (BET) results showed the increased surface area of Li_xTi_1-xO₂ NPs with increasing Li content. Li_xTi_1-xO₂ NPs (x = 0.05-0.20) working electrodes illustrated a pseudocapacitive behavior with excellent electrochemical properties through the whole cycles of GCD test. Interestingly, Li_0.1Ti_0.9O₂ NPs electrode illustrated a high performance in terms of maximum specific capacitance 822 F g^-1 at 1.5 A g^-1 in 0.5 M Li₂SO₄ electrolyte, with excellent capacitive retention 92.6% after 5000 cycles GCD test.