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Carson D. Ziemke

Publications and source records attributed to Carson D. Ziemke.

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$Ab$ $initio$ Study of Substitutional Defects in Li$_{3}$OCl Solid Electrolyte for Li-ion Batteries

Improving ion transport in solid electrolytes and cathode coatings remains a key challenge for all-solid-state Li-ion batteries because their room-temperature ionic conductivity is still substantially lower than that of liquid electrolytes. In our previous combined experimental and theoretical study, we showed that thermal neutron irradiation enables defect engineering in LiBO$_2$ through the transmutation of $^6$Li and $^{10}$B, generating lattice vacancies that enhance ionic conductivity. Here, we examine whether this approach can be extended to Li$_3$OCl, a representative antiperovskite solid electrolyte. Using density functional theory, we investigate substitutional defects at Li sites involving B, He, and H, associated with B doping and the neutron-capture reactions $^{6}\mathrm{Li}+n\rightarrow\,^{3}\mathrm{H}+α$ and $^{10}\mathrm{B}+n\rightarrow\,^{7}\mathrm{Li}+α+γ$. We evaluate defect formation energetics, the resulting structural distortions, and compare these substitutional defects with other mono-, di-, and trication substitutions at Li sites. Our results show that substitutional defects associated with neutron irradiation provide a feasible route to tune the defect chemistry of antiperovskite solid electrolytes and support neutron-driven defect engineering as a strategy for developing advanced materials for high-performance all-solid-state Li-ion batteries.

cond-mat.mtrl-sci

Neutron-Induced Enhancement of Ion Transport Through Lithium-Ion Battery Materials

Polycrystalline solid-state ionic conductors (SSICs) are essential energy materials for all-solid-state Li-ion batteries. To date, achieving a room-temperature ionic conductivity of solid electrolytes comparable to that of their liquid counterparts remains a critical challenge. Here, we experimentally demonstrate that thermal neutron irradiation can offer an innovative strategy in that neutron-induced modification in an SSIC model (LiBO$_{2}$ as an effective cathode coating) can facilitate ion transport through the material, enhancing its ionic conductivity. The central concept is that high-flux ($\sim 10^{9}\text{ neutrons}\cdot \text{cm}^{-2}\cdot \text{s}^{-1}$) thermal neutrons ($\sim \text{25 meV}$) selectively transmute strong neutron absorbers [which are $^{10}$B (3840 barns) and $^{6}$Li (940 barns) isotopes and present in their natural abundances of $\sim 19.9\%$ and $\sim 7.5\%$, respectively, in polycrystalline grains of LiBO$_2$] to generate lattice vacancies without compromising their crystallographic long-range order. In addition, by-product gamma photons emitted from $^{10}$B transmutation free electrons to stop atomic displacement and simultaneously neutralize the space charge built up by positively-charged oxygen vacancies at grain boundaries. As a result, the ionic conductivity is increased by nearly 20\% for the grains and more than 80\% for the grain boundaries. This study validates theoretical predictions and highlights a vital strategy for boosting ion transport in ionic solids. Overall, this novel approach establishes a new revenue for broader applications and greater enhancements of advanced functional materials in their related solid-state ionic devices, including all-solid-state lithium-ion batteries.

cond-mat.mtrl-sci

Vacancy-induced Modification of Electronic Band Structure of LiBO$_{2}$ Material as Cathode Surface Coating of Lithium-ion Batteries

LiBO$_{2}$ is an electronic insulator and a promising surface coating for stabilizing high-voltage cathodes in lithium-ion batteries. Despite its potential, the functional mechanisms of this coating remain unclear, particularly the transport of lithium ions and electrons through LiBO$_{2}$ in the presence of lattice vacancies. This understanding is critical for the design and development of LiBO$_{2}$-based materials. In our previous work [Ziemke $\textit{et al.}$, J. Mater. Chem. A, 2025, $\textbf{13}$, 3146-3162], we used density functional theory (DFT) calculations to investigate the impact of lattice vacancies on Li-ion transport in both tetragonal (t-LBO) and monoclinic (m-LBO) polymorphs of LiBO$_{2}$, revealing that B vacancies in either polymorph enhanced lithium-ion transport. In this study, we expand on these findings by using DFT calculations to examine the effects of lattice vacancies on the electronic properties of both t-LBO and m-LBO polymorphs,focusing on the electronic band structure. Our analysis shows that B vacancies can enhance the electronic insulation of t-LBO while improving the ionic conduction of m-LBO. The combined results of our previous and current works indicate that B vacancy generation in LiBO$_{2}$ may enable t-LBO to function as a promising solid electrolyte and enhance the performance of m-LBO as a conformal cathode coating in lithium-ion batteries. Overall, generating B vacancies, such as through neutron irradiation, would offer a viable strategy to improve the functionality of LiBO$_{2}$ as a promising material for energy storage applications.

cond-mat.mtrl-sci