SiO2@NiO core–shell nanocomposites as high performance anode materials for lithium-ion batteries

Abstract

SiO₂@NiO core–shell nanocomposites of ca. 80 nm in diameter with a thin NiO shell were assembled via a facile online deposition of NiO and investigated as an anode for lithium ion batteries. The results indicated that the specific discharge capacity of the obtained SiO₂@NiO core–shell nanocomposite electrode still retains 585 mA h g⁻¹ at a discharge current density of 100 mA g⁻¹ after 60 cycles and presents a coulombic efficiency of almost 100%, exhibiting good cycling stability and excellent rate capability after the first few cycles. This might be accounted for by the reversible lithiation/delithiation of the product Si due to the irreversible lithiation of SiO₂ while the irreversible lithiation of NiO to produce metal Ni nanoparticles is responsible for the activation of SiO₂, which is demonstrated by comparing the cyclic voltammetries (CVs) and electrochemical impedance spectra (EIS) of SiO₂, NiO and SiO₂@NiO electrodes.