Un-Gi Jong

Cu-coated graphene-reinforced aluminum matrix composites (AMCs) exhibit 1.5 times stronger interfacial bonding than the non-Cu-coated derivative due to hybridization between the 3d orbital of Cu and π orbital of graphene.

In this work, we comprehensively investigate materials properties such as not only structural, electronic, chemical bonding and lattice dynamics properties but also mechanical and dynamical stabilities for Li- and Sc-based borohydride LiSc(BH ₄ ) ₄ by using first-principles calculations. We make a reliable prediction of lattice parameters, bandgaps, elastic constants, dehydrogenation temperature and materials stability, providing atomic-scale insights into materials properties. Electronic structure calculations demonstrate that LiSc(BH ₄ ) ₄ and B ₂ H ₆ have large bandgaps over 4.5 eV and LiB has a small bandgap of ∼0.1 eV, whereas ScB ₂ has metallic electronic properties with no bandgap. Based on lattice dynamics calculations, we further reveal that all the compounds are dynamically stable at ambient conditions as well as mechanically stable in accordance with Born’s stability criteria. We suggest a dehydrogenation pathway and study energetics for H ₂ decomposition of LiSc(BH ₄ ) ₄ by considering quantum effect, finding that H ₂ desorption temperature ranges from 310 to 330 K. This work highlights that the borohydride LiSc(BH ₄ ) ₄ has high potentiality to be used as a promising H ₂ storage material with a high gravimetric capacity of 14.4[ ]wt.% and suitable dehydrogenation temperature.

We investigated the lattice dynamics and transport properties of lead-free quadruple halide perovskites Cs ₄ CuSb ₂ Cl ₁₂ , demonstrating its dynamic and mechanical stabilities and an ultralow κ _l .

We systematically investigated the hydrogen storage properties of the double-perovskite-type hydride LiNaMg₂H₆, demonstrating the material’s stability, high storage capacities of 7.09 wt%, 91.12 g L⁻¹, suitable dehydrogenation temperature of 540 K.

We systematically investigated hydrogen storage properties of hydride perovskite ACaH₃ (A = Li, Na), demonstrating materials stability, high storage capacities of 5.99 wt% and 63.77 g L⁻¹ and suitable dehydrogenation temperature of 450 K for LiCaH₃.

A first-principles study on the thermoelectric properties of the copper-based ternary phosphide CaCuP is presented. Self-energy relaxation time approximation and unified theory for lattice transport provide an accurate description of electron–phonon and phonon–phonon scattering. Our work provides an atomistic insight into its high thermoelectric performance, highlighting that nano-structuring can increase the thermoelectric figure of merit ZT by reducing the lattice thermal conductivity.

Exploring thermoelectric materials with high performance and low cost is of great importance in mitigating environmental and energy challenges. Here, we provide an atomistic insight into strain-induced enhancement of thermoelectric performance in potassium-based halide double perovskite K2SnX6 (X = I, Br, Cl) using first-principles calculations. To get reliable predictions for transport properties, we adopt advanced methods such as self-energy relaxation time approximation for electron transport and unified theory for lattice transport in combination with self-consistent phonon approach. Our calculations highlight a promising thermoelectric figure of merit ZT over 1.01 in K2SnI6 when applying a compressive strain of −6%, being tenfold larger than those in the uncompressed compounds, suggesting that compressing is an effective way to enhance the thermoelectric performance of halide double perovskites.

In spite of extensive studies on halide perovskites for advanced photovoltaic applications, little attention has been paid to fluoride perovskites so far.

First-principles calculations have been performed to study structural, elastic, electronic and optical properties of all-inorganic halide double perovskites Cs ₂ AgBX ₆ (B = In, Sb; X = F, Cl, Br, I) for solar cell and light emission applications.

Metal phosphides have recently emerged as promising thermoelectric materials with high performance and low cost of constituent elements. In this work, we provide atomistic insight into thermoelectric performance of ternary metal phosphide CaAgP using first-principles calculations of transport properties, focusing on an accurate description of phonon–phonon and electron–phonon interactions. Applying a unified theory for lattice thermal conductivity and momentum, self-energy relaxation time approximation approaches for phonon-limited electronic transports result in overall agreement with experiment for transport properties of CaAgP. Having a promising thermoelectric figure of merit ZT over 0.48 at 650 K, nano-phasing or doping is suggested to further enhance the thermoelectric performance.