Electrochemical Energy Storage Mechanism of Networked Cobalt Oxide/Ceria Nanostructured Films through Two Immiscible Electrolyte Solutions

Lithium-ion batteries power a wide range of contemporary products due to their high energy density, extended cycle life, and relatively low self-discharge rate. Here, innovative methods are being investigated to enhance the electrochemical performance of Li-ion batteries, including the design of a Li-ion battery based on a networked Co3O4/CeO2 nanostructured electrode within two immiscible electrolyte solutions. As a result, the specific capacity of the networked Co3O4/CeO2 nanostructured film in a lithium hexafluorophosphate aqueous electrolyte is approximately 378 C g–1 at a scan rate of 50 mV s–1, which is much higher than those of single-phase Co3O4 and CeO2 films. On the other hand, the charge storage capacity of the networked Co3O4/CeO2 nanostructured film in a two-immiscible water–toluene electrolyte is higher than that in an aqueous electrolyte, with a specific capacity of approximately 975 C g–1 due to the fact that the specific partitioning of the electrolyte ions (Li+ and PF6–) at the water–toluene interface increases the concentration of electroactive species near the electrode surface compared to a water electrolyte. This study lays the groundwork for investigating and developing innovative Li-ion batteries based on two immiscible electrolyte solutions, which will lead to more affordable energy storage devices.