ZIF-Derived Cobalt-Containing N-Doped Carbon-Coated SiO_<i>x</i> Nanoparticles for Superior Lithium Storage

Abstract

N-Doped carbon-encapsulated SiO_<i>x</i> and Co nanoparticles are synthesized by the calcination of ZIF-67-coated SiO_<i>x</i> nanoparticles. This composite exhibits good electrochemical conductivity and superior accommodation to volume change from N-doped carbon and Co with SiO_<i>x</i> nanoparticles, exhibiting improved cycle and rate performances for lithium storage. It retains a capacity of 1044 mA h g^-1 over 150 cycles at 1.5 A g^-1, outperforming those without Co or N-doped carbon. It well confirms the contributions of Co- and N-doped carbon to the electrochemical properties of SiO_<i>x</i>. Even after 350 cycles at 1.0 A g^-1, this composite nonetheless delivers a capacity of 900 mA h g^-1. If it is coupled with LiFePO₄, the full cells show a stable cycling, indicating the promising application of this composite.