Carbon nano-onions/tubes catalyzed by Ni nanoparticles on SiOx for superior lithium storage

SiOx anode is considered as one of the most promising anode materials for lithium-ion batteries due to its high specific capacity (2000-2500mAh g−1). However, its low electron conductivity and huge bulk expansion during cycle hinder its practical application. Therefore, we have designed and fabricated a SiOx-based three-dimensional composite conductive carbon network, including Ni nano particles (NNPs) decorated SiOx core, carbon nano-onions (CNOs) and carbon nanotubes (CNTs), where NNP and CNOs/CNTs were prepared by using chemical bath deposition (CBD) followed by a reduction reaction and plasma-enhanced chemical vapor deposition (PECVD), respectively. As a transition metal, NNP not only improve the conductivity of the composite powders, but act as a catalyst for the growth of carbon materials, i.e., CNOs and CNTs herein. As designed composite material formed a highly conductive three-dimensional structure (SiOx/Ni/CNOs-CNTs) to protect SiOx from the direct contact with the electrolyte, and alleviate the volume expansion in the lithiation process. As an anode in lithium-ion battery, SiOx/Ni/CNOs-CNTs has a reversible specific capacity of 663.9 mAh g−1 after 500 cycles at a current density of 1 A g−1 (with a capacity retention rate of 94.1%), and a reversible specific capacity of 430.9 mAh g−1 at a current density of 2 A g−1.