Magnetic field-governed kinetics in a silicon dioxide-based anode towards high performing lithium-ion magneto-batteries

Abstract

Due to low intrinsic electrical conductivity, sluggish electrode kinetics occur in silicon dioxide (SiO₂) as an anode material, which along with its low initial coulombic efficiency (CE) restrict its use in lithium-ion batteries (LIBs). Herein, a magnetic field is employed within the cell to control the magnetoresistance of the SiO₂ electrode, which not only enhances the overall performance but also improved the initial CE. In this regard, a chemical vapor deposition technique is used to deposit in situ SiO₂ on the copper foil substrate, which is used directly to assemble a battery cell under a magnetic field. Although SiO₂ is not a magnetic material, defects in SiO₂ behave like a nano magnet under an applied magnetic field, which reduces scattering and random movement of charge carriers and aligns them towards conductive channels within the materials. As a result, charge carriers obtained from lithium-ions (Li⁺) on the anode surface travel through conductive channels due to which promising battery performance is observed. First, the SiO₂/Cu electrode is used as an anode under different magnitudes of magnetic field (i.e. 800–2400 gauss) and an improvement in the initial CE but a lower negative magnetoresistance were observed. To increase the negative magnetoresistance of SiO₂/Cu, in situ carbon is also coated, which offers an exceptional initial CE ∼ 96%, an excellent capacity retention even after long-term cycling for 1000 cycles (i.e., 2050 mA h g⁻¹ at 100 mA g⁻¹) and a commendable high-rate capability (i.e., 891 mA h g⁻¹ at 2 A g⁻¹). No doubt, the obtained findings are critical to developing high performing battery systems by coupling magnetoresistance with electrode kinetics.