Author ORCID Identifier

0000-0002-0899-5044

Biosketch

I am specialized in synthesizing transition metal carbide MAX phase and MXene nanoflakes for energy storage (supercapacitor) and electrocatalysis (hydrogen evolution reaction) applications. With a passion for exploring new 2D nanomaterials, my work focuses on synthesis and characterization of MXene nanoflakes. Through rigorous experimentation and analysis, I aim to contribute to the advancement of 2D nanomaterials, addressing the ongoing energy crisis with innovative solutions.

Date of Award

9-3-2026

Document Type

Thesis

School

School of Electrical & Electroncis Engineering

Programme

Ph.D.-Doctoral of Philosophy

First Advisor

Dr.S.Ayyappan

Keywords

Max Phase, Mxene Nanoflakes, Super Capacitor, Electrocatalyst, Hydrogen Evolution Reaction

Abstract

Rapid growth in population and industrialization created a huge demand for superior energy storage devices. Thus, the researchers are in constant search of developing exotic materials towards energy harvesting and storage devices. Batteries, supercapacitors, and fuel cells received a great attention to meet the global demand for energy storage. Among them, supercapacitors are widely preferred as energy storage devices due to higher power density, longer cycle life, and fast charging. The performance of the supercapacitors highly depends on the choice of electrode materials and electrolyte.

Recently, “MXenes”  a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered a new class of layered two-dimensional (2D) nanomaterials have been widely employed as electrode material in energy storage applications due to their exciting properties such as high electrical conductivity, large surface area, tuneable surface chemistry, and hydrophilic nature.

Among various MXenes, Ti3C2Tx is one of the mostly studied 2D material due to the easy synthesis, scale-up and abundant surface termination groups (Tx). Ti3C2Tx MXene is synthesized from the Ti3AlC2 MAX phase a class of hexagonal layered transition metal carbides, nitrides and carbonitrides. MAX phases are synthesized by various methods including spark plasma sintering, hot pressing, molten salt synthesis, and pressureless sintering at a relatively high temperature (> 1000℃). Despite various synthesis approaches, homogeneous mixing of elemental precursor powders play vital role in uniform distribution of particles and control over the final composition.

Traditionally, a high energy ball milling unit extensively used for mixing the elemental powders though it is time consuming (10 72 h 72 hr). Further, frictional effect between the powder and balls causes undesired oxidation and contamination of the precursor powders. Therefore, it is necessary to look for an alternative method of mixing the elemental precursor powders without compromising the mixing efficiency. In this thesis, Ti3AlC2 MAX phase is synthesized by using a probe sonication (PS) assisted mixing of elemental precursor powders followed by pressureless sintering under inert atmosphere. A detailed study reveals that a sonication time of 60 min followed by pressure-less sintering at 1500℃ for 2 hr in inert condition produces >99% phase pure Ti3AlC2 MAX.

Further, pristine Ti3AlC2 MAX phase is used as the main precursor to synthesis multilayered (MLTi 3C2Tx) and delaminated (dTi 3C2Tx) MXene. The electrochemical performance of the delaminated dTi 3C2Tx MXene exhibits a specific capacitance of 255 F g1 at a specific current of 0.5 A g1. Further, d – Ti3C2Tx retained 88.6% capacitance and 100% coulombic efficiency over 5,000 cycles at 5 A g1. A symmetric supercapacitor fabricated using d – Ti3C2Tx MXene delivered a specific energy of 1.75 Wh kg1 at a specific power of 194.32 W kg1 and retains 68.5% capacitance over 5,000 cycles. The electrocatalytic activity of multilayered (MLTi 3C2Tx) MXene towards hydrogen evolution reaction (HER) in acidic medium shows a better HER activity with a low overpotential of 147 mV at a current density of 10 mA cm2. Further, ML–Ti3C2Tx showed a two-fold increase in the HER activity under continuous operation (50 hr, 5,000 cycles) when compared with Pt/C, suggesting good stability and durability in hydrogen production at a high rate in an acidic medium. Therefore, the present thesis work suggests the effective synthesis of phase pure Ti3AlC2 MAX by a facile PS approach.

Additional Files
Graphical Abstract Srikanth Ragunath B.pdf (502 kB)
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Graphical Abstract