Subtractive synthesis of anatase TiO2 nanostructures for sustained Li-storage in faradaic and non-faradaic assemblies

Titanium dioxide has been considered one of the promising anode materials for energy storage applications since the 1980s, especially in lithium-ion batteries (LIBs). Among the different polymorphs, the anatase phase of titanium dioxide (a-TiO₂) exhibits an excellent composition of physical and chemical properties with high capacity, superior rate capability, and cyclability. Herein, we report a method of reverse synthesizing TiO₂ through the leaching of lithium titanate (Li₄Ti₅O₁₂, LTO). The physical and chemical properties of the synthesized a-TiO₂ were examined through various characterization techniques, and its formation was confirmed. Initially, the electrochemical Li-storage ability of the a-TiO₂ was analyzed through Li/a-TiO₂ half-cell assembly. Further, LIB and lithium-ion capacitors (LICs) were fabricated by pairing a-TiO₂ with LiNi_0.5Mn_1.5O₄ (LNMO) and activated carbon (AC), respectively. A maximum energy and power density of 188 and 73 Wh kg⁻¹ was shown by LNMO/a-TiO₂ (LIB) and AC/a-TiO₂ (LIC) assemblies, respectively. Both the LIB and LIC exhibited good cyclability and excellent adaptability at various temperatures.