Swallow-Nest Architectures with Cobalt Molybdate Particulates Fixed Constructed Carbon Nanotube Supports for Stable Sodium-Ion Battery Anode

A swallow-nest architecture is fabricated through in situ prefabricated heating using cobalt molybdate (CoMoO₄) as the subject and acid-functionalized carbon nanotubes (AF-CNTs) as the skeleton (CoMoO₄/AF-CNT nest). The CoMoO₄/AF-CNT nest is fixed via the C-O-Mo bond between the AF-CNT supports and CoMoO₄ nanoparticles and hydrogen bonds of neighboring CNTs. The size of CoMoO₄ in the CoMoO₄/AF-CNT nest is confined to the nanometer level (30 nm), which will lead to negligible nanoscale volume changes during charge and discharge. The swallow-nest architecture can enhance the stability of the electrode, thus accelerating electrolyte penetration and providing fast diffusion channels for charge and Na⁺ ion transfer. When used as the anode of sodium-ion batteries, the CoMoO₄/AF-CNT nest electrodes exhibit a reversible capacity of 151.6 mA h g^-1 at the promising current densities of 2.0 A g^-1 with degradation rate lower than 5.4 μA h g^-1 cycle^-1 after 2000 cycles.