Investigation of Metal Tellurides As Cathode Materials for High-Energy Lithium-Tellurium Batteries

Lithium-tellurium (Li-Te) batteries are gaining attention as a promising next-generation energy storage system due to their superior electrical conductivity and high volumetric capacity compared to sulfur and selenium. Tellurium's unique properties, such as suitable redox potential, excellent conductivity, high volumetric capacity, and greatest stability, position it as a strong candidate for negative electrode materials. This study explores the potential of metal tellurides, specifically CuTe and FeTe monolayers, as effective tellurium host materials, leveraging their polar interactions with lithium polytellurides. Using density functional theory (DFT) approaches, we investigated the thermodynamic stability, adsorption behavior, and conversion performance of lithium polytellurides on experimentally synthesized metal tellurides. ab initio molecular dynamics (AIMD) simulations confirmed the stability of these materials at 300 °C, 350 °C, and 400 °C. Our findings indicate that the CuTe monolayer provides a strong anchoring effect on lithium polytellurides and exhibits the lowest conversion barrier from Te₈ to Li₂Te, significantly enhancing electrochemical reaction dynamics and reducing the shuttle effect. Additionally, CuTe demonstrated a low activation energy of 0.297 eV for a key Li₂Te reaction and strong adsorption energy (-3.511 eV), as well as low diffusion activation energy for Li ions. In addition to the interaction with lithium polytellurides, solvent adsorption studies revealed moderate adsorption energies for CuTe, ranging from -43.435 to -54.297 kJ/mol for solvents like DEC, DMC, DME, DOL, EC, EMC, and PC, suggesting strong, but nondisruptive, binding interactions with electrolyte solvents. Lithium adsorption energies with these solvents, which ranged from -0.359 eV to -0.648 eV, further indicate the stability of the system in typical electrolyte environments. These properties, along with its effective solvent adsorption capabilities, suggest that CuTe is a highly promising candidate for cathode materials in Li-Te batteries. Our results provide valuable insights for the design and optimization of Li-Te batteries, advancing the development of efficient and stable energy storage systems.