Potassium titanate-based two-dimensional electrode material for high-current density supercapacitors

Abstract

Background

Supercapacitor-based energy storage devices are gaining popularity because of exceptional performance such as fast charging, long lifespan, stability, and enormous energy and power densities. Developing cost-effective energy storage systems is highly justified in light of the anticipated energy demand. For these reasons, cost-effective potassium-based electrode material is explored in this study for high-performance supercapacitor applications.

Methods

This study proposes a simple hydrothermal method to create a novel, cost-effective, two-dimensional potassium titanate (K₂Ti₄O₉) nanosheets as an electrode material in supercapacitors (SCs). X-ray diffraction analysis (XRD), high-resolution scanning electron microscopy studies (HR-SEM), energy dispersive X-ray analysis spectrum (EDX), Raman spectroscopy, and high-resolution transmission electron microscopy studies (HR-TEM) analysis were used to characterize the as-synthesized material. Cyclic voltammetry and galvanostatic charge-discharge techniques were employed in the electrochemical experiments.

Significant findings

The synthesized K₂Ti₄O₉ nanosheet-based electrode materials exhibited a remarkable specific capacitance of 324 F/g at a current density of 2 A/g for up to 8500 cycles. It also shows ∼98% coulombic efficiency and ∼94% capacitance retention at 2 A/g. Moreover, we constructed an asymmetric device and demonstrated LED light using K₂Ti₄O₉ nanosheets, which display 54 Wh/kg and 485 W/kg energy and power densities, respectively.