Enhancing the Electrical Conductivity of Iron-Oxide-Based Anodes by Tin-Oxide-Based Coating for Lithium-Ion Batteries

With the increasing global demand for energy storage, developing lithium-ion batteries (LIBs) with higher energy density and improved safety is becoming increasingly critical. Iron oxides exhibit the advantages of high capacity, earth abundance, non-toxicity, and low flammability, making them potential candidates as anode materials. However, their practical application is hindered by poor conductivity, low Coulombic efficiency, and structural degradation during cycling. Therefore, it is necessary for innovative strategies to enhance their electrochemical performance.

Surface coating is an effective strategy to improve the electrical conductivity, structural stability, and durability of LIB anodes. This work focuses on developing a tin-oxide-based coating on iron-oxide-based active materials for LIB anodes. Tin-oxide-based materials are chosen for their unique combination of good conductivity and high theoretical capacity, which one usually needs to be provided by combining different materials together. The anode electrical conductivity is improved by optimizing the coating parameters, including thickness, process temperatures, ambience, and pressure in a quartz tube, so as to enhance the battery electrochemical performance.

The coated iron-oxide-based powders will be combined with carbon black (Super P), carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR) to create an aqueous-based slurry. This slurry will be applied onto a copper foil using a doctor-blade coating technique to fabricate electrodes, which will then be dried in a vacuum oven. Following battery assembly, galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) will be performed to evaluate the improvements in electrical conductivity, rate-capability, cycling stability, and impedance reduction attributed to the tin-oxide-based coating. Additionally, the tin-oxide-based coating layer will be characterized using Raman spectroscopy, scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). This work is expected to improve the electrical conductivity of the anode material in LIB anodes by applying tin-oxide-based coatings on iron-oxide-based anodes. This enhancement will enhance the battery electrochemical performance, advancing the development of high-performance LIBs.