Pumice Additives in Iron Oxide for Solid-State Lithium-Ion Batteries

Solid-state lithium-ion batteries are indispensable for the next-generation energy storage device because of their safety and lightweight. High-capacity, low-cost, earth-abundance, and low flammability make iron oxides a promising active material for solid-state batteries. However, one of the shortages of both iron oxide actives and solid-state batteries is poor ionic conductivity, causing the short cycle life of batteries.<br/><br/>Pumice, a natural silicon oxide-based porous material formed through volcanic activities, is selected as an additive candidate in iron oxides for solid-state battery applications. Pumice is expected to act as an ion transport path that can effectively reduce the diffusion path length between actives, resulting in lower impedance and overpotential. Therefore, it will lead to a higher rate-capability, shorter reaction time, and enhanced retention. Besides, pumice is earth-abundant and environmentally sustainable. Utilizing pumice as an additive offers a simple method to recycle flooding volcanic pyroclastic flow.<br/><br/>The composition of iron oxide actives with pumice additives will be optimized. The actives will be mixed with carbon black (super P), carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR) to form a water-based slurry. The slurry will be further coated on a copper foil through the doctor-blade coating process. The fabricated electrode will be dried in a vacuum oven and then assembled into batteries. The pumice morphology and structure will be characterized by field-emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectrometry (EDX), respectively. Galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) analyses will be applied to analyze the charge/discharge cycle life, Coulombic efficiency, and impedance resulting from the addition of pumices. These analyses will be used to investigate the mechanism of pumice additives in iron oxides.<br/><br/>This work will offer insights into using pumice additives to enhance the retention of solid-state batteries for future applications.