By Elise Henry, Clara LaMoy

Faculty Mentor: Dr. Leanna Giancarlo

Abstract

Lithium-ion batteries dominate modern energy storage; however, alternative alkali metals, such as sodium (Na) and potassium (K), are being explored due to lithium (Li) resource limitations and performance optimization needs. Ionization energy, defined as the energy required to remove an electron from a neutral atom, plays a key role in determining how readily a metal participates in the electron-transfer (redox) reactions that power batteries. Therefore, ionization energy trends for Li, Na, and K were analyzed using computational chemistry methods based on solutions to the Schrödinger equation, which describes electron behavior in atoms. Using GAMESS via ChemCompute, STO-3G and 3-21G basis sets with Hartree–Fock theory were applied to approximate atomic energies for multi-electron systems and calculate ionization energies from the energy difference between neutral atoms and their cations. The STO-3G basis set produced ionization energies of 4.90 eV (Li), 3.80 eV (Na), and 1.86 eV (K), with percent errors relative to experimental values from −8.04% to −57.1%. The 3-21G basis set improved results to 5.29 eV, 4.91 eV, and 3.98 eV, with errors from −0.73% to −8.23%; in both cases, deviation increased with electron number. Lower ionization energies favor electron release in electrochemical reactions relevant to battery operation, with K showing the lowest values among the atoms studied, suggesting a greater tendency for electron donation. However, these calculations consider only a single atomic property, highlighting both the value of computational chemistry in understanding electronic structure and its limitations when evaluating battery performance.