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

Abstract

Low intrinsic electrical conductivity due to which sluggish electrode kinetics occurs in silicon dioxide (SiO2) as anode material and low initial Coulombic efficiency (CE) bottleneck its use in lithium-ion batteries (LIBs). Herein, a magnetic field is employed within the cell to control magnetoresistance of SiO2 electrode which not only enhances 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 battery cell under a magnetic field. Although, SiO2 is not a magnetic material, but defects in SiO2 behave like a nano magnet under applied magnetic field which reduces scattering, and random movement of the charge carriers and certainly align them towards conductive channels within the materials. As a result, charge carriers obtained from lithium-ion (Li+) on the anode surface travel through conductive channels due to which promising battery performance is observed. First, SiO2/Cu electrode is used as anode under different magnitude of magnetic fields (i.e. 800-2400 Gauss) and observed improvement in initial CE but lower negative magnetoresistance. To increase 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 1000 cycles (i.e., 2050 mAh g-1 at 100 mA g-1) and a commendable high-rate capability (i.e., 891 mAh g-1 at 2 Ag-1). No doubt, the obtained findings are critical to develop high performing battery system by coupling magnetoresistance with electrode kinetics.