One-dimensional lepidocrocite titania mesoparticles integrated with activated carbon for high-performance supercapacitor applications

Herein, we mix titania-based, TiO 2 , porous mesostructured, comprised of one-dimensional lepidocrocite nanofilaments, 1DLs, ≈ 5 × 7 Å 2 in cross-section, with activated carbon, AC, to create unique composite structures with exceptional electrochemical properties. The synthesis method is facile, cost-effective, and scalable. While the porous mesoparticles, PMs, possess excellent protonic conductivity and exhibit enhanced faradic behavior in acidic aqueous media, their low electronic conductivity restricts their power output. The problem is solved by mixing the PMs with AC powders with various loadings. Electrolytes used were sulfuric acid, H 2 SO 4 , potassium hydroxide, KOH, lithium and Na-sulphates. The best PM loading was found to be 25 wt%. The resulting composite exhibits a specific capacitance (capacity) of 1024 Fg −1 (554 mAhg −1 ) at a 2 mVs −1 scan rate, with 97 % cyclic stability over 10,000 cycles when the electrolyte was 1 M H 2 SO 4 . Upon integration into a symmetrical device, the composite exhibited a specific energy of 135 Whkg −1 at 0.5 Ag −1 . Further, it demonstrated a peak specific power of 18 kWkg −1 , while retaining a specific energy of 54 Whkg −1 at 5 Ag −1 . Notably, following 100,000 cycles at 1 Ag −1 , the symmetrical cell sustained approximately 50 % of its initial specific capacitance. Subsequently, a 24 h self-discharge test revealed a decrease in cell voltage from 1.95 V to 0.48 V, thereby highlighting the potential suitability of these supercapacitors for short-term energy storage applications. • A unique composite of 1D lepidocrocite titania nanofilaments (5x7 Å 2 ) with activated carbon for improved supercapacitor. • Symmetric supercapacitor exhibits high specific capacitance and energy in 1.95V potential window in aqueous electrolyte. • The capacitance retention of the cell is up to 95% over 10,000 cycles and ~50% after 100,000 cycles.