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Modification using carbon nanotubes (CNTs) is one of the most important strategies to boost the performance of materials in various applications, among which the CNT-modified silicon-based anodes have gained considerable attention in lithium-ion batteries (LIBs) due to their improved conductivity and cycle stability. However, the realization of a close-knit CNT coating on silicon (Si) through an efficient and cost-effective approach remains challenging. Herein, a new in situ self-catalytic method by acetylene treatment is presented, in which, CNTs can be directly grown and knitted on the SiOx particles to construct a conductive additive-free SiOx@CNT anode. The in situ grown CNTs can not only enhance electric conductivity and alleviate the volume effect of SiOx effectively, but also mitigate the electrolyte decomposition with improved coulombic efficiency. As a result, an extremely high capacity of 1012 mA h g−1, long lifespan over 500 cycles at a current density of 2 A g−1 as well as a good performance in full LIBs with a working potential of about 3.4 V (vs. nickel-rich cathode) were obtained. The rationally constructed SiOx@CNTs with easy synthesis and high throughput will hopefully promote LIBs with energy density above 300 W h kg−1. This study opens a new avenue to prepare CNT-decorated functional materials and brings the SiOx-based anode one step closer to practical applications.

New hierarchical hollow SiO2 spheres (HHSs) decorated with metal nanoparticles (i.e., Co, Co–HHS) were designed using an in situ self-assembly approach. The Co nanoparticles were found to have a catalytic effect on (de-)lithiation of SiO2 and hence in storing lithium. Then, an extremely high capacity of 932 mA h g−1 and good cycling stability for more than 1000 cycles were demonstrated in the corresponding lithium battery. In addition, the lithium-ion full batteries of the Co–HHS versus lithium layered oxide cathode (e.g., LiNi1/3Co1/3Mn1/3O2, NCM333) were introduced and showed good performance, demonstrating the promising application of the Co–HHS, in particular for pursuing high-energy-density batteries.

Silica is a very promising anode material for lithium-ion batteries, due to its advantages of being resource-rich and having high theoretical specific capacity. However, poor electrochemical activity severely limits its practical application. To solve this issue, a nanosheet-assembled silica hierarchical hollow sphere decorated with ultrafine cobalt nanoparticles and carbon (SiO2/Co/C) is successfully synthesized. The hollow structure can effectively alleviate the volume expansion, shorten the migration distance of lithium ions, and increase the binding site. Furthermore, the carbon matrix and highly active ultrafine cobalt nanoparticles enhance not only the electronic conductivity but also the electrochemical activity (catalyzing the breaking of Si–O and Li–O bonds) of SiO2. The resulting SiO2/Co/C composite has a high reversible capacity of 1160 mA h g−1 at 0.2 A g−1 and still has a specific capacity of 548 mA h g−1 after 1000 cycles at a high current density of 1.0 A g−1. Moreover, the SiO2/Co/C composite also exhibits good electrochemical performance in a full cell.