arXiv subjects

Zhen-Dong Huang

Publications and source records attributed to Zhen-Dong Huang.

5 recordsLinked to original sources

arXiv2023

Advances in honeycomb layered oxides: Part I -- Syntheses and Characterisations of Pnictogen- and Chalcogen-Based Honeycomb Layered Oxides

Advancements in nanotechnology continue to unearth material vistas that presage a new age of revolutionary functionalities replete with unparalleled physical properties and avant-garde chemical capabilities that promise sweeping paradigm shifts in energy, environment, telecommunications and potentially healthcare. At the upper echelons of this realm, the pnictogen and chalcogen class of honeycomb layered oxides have emerged with fascinating crystal chemistry and exotic electromagnetic and topological phenomena that muster multifaceted concepts spanning from materials science to condensed matter physics and potential applications in electrochemistry, quantum mechanics and electronics. In a bid to shed light on the mechanisms governing these biomimetic nanostructures, this review highlights the significant milestones and breakthroughs that have augmented their current fundamental theory, properties, and utilities. Herein, we elucidate the vast promising crystal chemistry space against the backdrop of known synthesis and characterisation techniques employed in the development and optimisation of this class of honeycomb layered oxides. Further, we highlight key theoretical models that have reinvigorated the exploration and characterisation of within this class of materials and are poised to redefine the frontiers of material research and their applications. We conclude by envisaging future research directions where fascinating physicochemical, topological and electromagnetic properties could be lurking and where valiant efforts ought to be inclined, particularly in the prospective realisation of exotic material compositional space as well as their utility as testing grounds for emergent two-dimensional (2D) topological quantum gravity and conformal field theories.

cond-mat.mtrl-sci↗

arXiv2022

Honeycomb Layered Oxides With Silver Atom Bilayers and Emergence of Non-Abelian SU(2) Interactions

Honeycomb layered oxides with monovalent or divalent, monolayered cationic lattices generally exhibit myriad crystalline features encompassing rich electrochemistry, geometries and disorders, which particularly places them as attractive material candidates for next-generation energy storage applications. Herein, we report global honeycomb layered oxide compositions, ${\rm Ag_2}M_2{\rm TeO_6}$ ($M = \rm Ni, Mg, \textit{etc}.$) exhibiting $\rm Ag$ atom bilayers with sub-valent states within Ag-rich crystalline domains of ${\rm Ag_6}M_2{\rm TeO_6}$ and $\rm Ag$-deficient domains of ${\rm Ag}_{2 - x}\rm Ni_2TeO_6$ ($0 < x < 2$). The $\rm Ag$-rich material characterised by aberration-corrected transmission electron microscopy reveals local atomic structural disorders characterised by aperiodic stacking and incoherency in the bilayer arrangement of $\rm Ag$ atoms. Meanwhile, the global material not only displays high ionic conductivity, but also manifests oxygen-hole electrochemistry during silver-ion extraction. Within the $\rm Ag$-rich domains, the bilayered structure, argentophilic interactions therein and the expected $\rm Ag$ sub-valent states ($1/2+, 2/3+, \textit{etc}.$) are theoretically understood via spontaneous symmetry breaking of SU($2$)$\times$U($1$) gauge symmetry interactions amongst $3$ degenerate mass-less chiral fermion states, justified by electron occupancy of silver $4d_{z^2}$ and $5s$ orbitals on a bifurcated honeycomb lattice. This implies that bilayered frameworks have research applications that go beyond the confines of energy storage.

cond-mat.mtrl-sci↗

arXiv2022

A Potential Cathode Material for Rechargeable Potassium-Ion Batteries Inducing Manganese Cation and Oxygen Anion Redox Chemistry: Potassium-Deficient $\rm K_{0.4}Fe_{0.5}Mn_{0.5}O_2$

Potassium-ion ($\rm K$-ion) rechargeable batteries; considered to be lucrative low-cost battery options for large-scale and capacious energy storage systems, have been garnering tremendous attention in recent years. However, due to the scarcity of cathode materials that can condone the reversible re-insertion of the large $\rm K$-ions at feasible capacities, the viability of $\rm K$-ion batteries has been greatly undercut. In this paper, we explore a potential cathode material in the $\rm K_2O$-$\rm Fe_2O_3$-$\rm MnO_2$ ternary phase system, that not only demonstrates reversible $\rm K$-ion reinsertion but also manifests relatively fast rate capabilities. The titled cathode compound, $\rm K_{0.4}Fe_{0.5}Mn_{0.5}O_2$, demonstrates a reversible capacity of approximately $\rm120 $ mAh g$^{-1}$ at $\rm 10$ hours of (dis)charge ($viz.$, $\rm C/10$ rate) with $ca.$ $\rm 85$% of the capacity being retained at a $\rm 1$ hour of (dis)charge ($\rm 1 C$ rate) which is considered to be good capacity retention. Additionally, both hard and soft X-rays have been employed to unravel the mechanism by which $\rm K$-ion is reversibly inserted into $\rm K_{0.4}Fe_{0.5}Mn_{0.5}O_2$. The results revealed a cumulative participation of both manganese cations and oxygen anions in $\rm K_{0.4}Fe_{0.5}Mn_{0.5}O_2$ illustrating its potential as a high-capacity $\rm K$-ion battery cathode material that relies on both anion and cation redox. Further development of related high-capacity cathode compositions can be anticipated.

cond-mat.mtrl-sci↗

arXiv2021

Mixed Alkali-Ion Transport and Storage in Atomic-Disordered Honeycomb Layered $\rm NaKNi_2TeO_6$

Honeycomb layered oxides constitute an emerging class of materials that show interesting physicochemical and electrochemical properties. However, the development of these materials is still limited. Here, we report the combined use of alkali atoms ($\rm Na$ and $\rm K$) to produce a mixed alkali honeycomb layered oxide material, namely, $\rm NaKNi_2TeO_6$. Via transmission electron microscopy measurements, we reveal the local atomic structural disorders characterised by aperiodic stacking and incoherency in the alternating arrangement of $\rm Na$ and $\rm K$ atoms. We also investigate the possibility of mixed electrochemical transport and storage of $\rm Na$ and $\rm K$ ions in $\rm NaKNi_2TeO_6$. In particular, we report an average discharge cell voltage of about $4\, \rm V$ and a specific capacity of around $80\, \rm mAh\, g^{-1}$ at low specific currents (i.e., $< 10\, \rm mA\, g^{-1}$) when a $\rm NaKNi_2TeO_6$-based positive electrode is combined with a room-temperature $\rm NaK$ liquid alloy negative electrode using an ionic liquid-based electrolyte solution. These results represent a step towards the use of tailored cathode active materials for dendrite-free electrochemical energy storage systems exploiting room-temperature liquid alkali metal alloy materials.

cond-mat.mtrl-sci↗

arXiv2020

Honeycomb Layered Oxides: Structure, Energy Storage, Transport, Topology and Relevant Insights

The advent of nanotechnology has hurtled the discovery and development of nanostructured materials with stellar chemical and physical functionalities in a bid to address issues in energy, environment, telecommunications and healthcare. In this quest, a class of two-dimensional layered materials consisting of alkali or coinage metal atoms sandwiched between slabs exclusively made of transition metal and chalcogen (or pnictogen) atoms arranged in a honeycomb fashion have emerged as materials exhibiting fascinatingly rich crystal chemistry, high-voltage electrochemistry, fast cation diffusion besides playing host to varied exotic electromagnetic and topological phenomena. Currently, with a niche application in energy storage as high-voltage materials, this class of honeycomb layered oxides serves as ideal pedagogical exemplars of the innumerable capabilities of nanomaterials drawing immense interest in multiple fields ranging from materials science, solid-state chemistry, electrochemistry and condensed matter physics. In this review, we delineate the relevant chemistry and physics of honeycomb layered oxides, and discuss their functionalities for tunable electrochemistry, superfast ionic conduction, electromagnetism and topology. Moreover, we elucidate the unexplored albeit vastly promising crystal chemistry space whilst outlining effective ways to identify regions within this compositional space, particularly where interesting electromagnetic and topological properties could be lurking within the aforementioned alkali and coinage-metal honeycomb layered oxide structures. We conclude by pointing towards possible future research directions, particularly the prospective realisation of Kitaev-Heisenberg-Dzyaloshinskii-Moriya interactions with single crystals and Floquet theory in closely-related honeycomb layered oxide materials.

cond-mat.mtrl-sci↗