Harnessing halides: Comparative study of oxide fullerene modifications for sodium ion secondary battery efficiency

The quest for secondary batteries drives ongoing research aimed at developing cost-effective and high-performance nanomaterials. While lithium-ion batteries initially offered high efficiency, however escalating demand has led to increased costs prompting exploration of other alternatives such as sodium (Na) ion batteries. Na resources are much more abundant and widely distributed globally compared to lithium. This study explores the potential of sodium ion battery by adopting a novel approach of incorporating endohedral halides into oxides fullerenes to enhance the voltage. We investigated the thermodynamic and electronic stabilities of Na/Na⁺ ions with both bare and halide-doped magnesium oxides (Mg₁₂O₁₂) and zinc oxides (Zn₁₂O₁₂) fullerenes to understand how encapsulated halide affects the structural and electrochemical properties. The bare oxide fullerenes exhibit cell voltages of 0.29 and −0.50 V in the presence of toluene solvent. Upon incorporation of various halide ions into oxides fullerenes, we obtained cell voltage in acceptable range for anode materials. Specifically, the variation in free energy experiences a remarkable improvement where the Cl⁻@Zn₁₂O₁₂ in toluene has the most appropriate cell voltage of 1.09 V in the presence of toluene solvent, among all halides adsorbed oxides nanocages. These findings provide valuable insights for the design of novel low-cost nanomaterials having better cell voltage. The endeavor additionally catalyzes further research work into the design of halide-encapsulated oxide-fullerene-based secondary batteries, intended for widespread applications in electrochemical energy storage devices. This comprehensive work serves as a detailed blueprint for experimentalists, facilitating the synthesis of such systems to address the future challenges posed by energy scarcity.