Cobalt Oxide 2D Nanosheets Formed at a Polarized Liquid|Liquid Interface toward High-Performance Li-Ion and Na-Ion Battery Anodes
Bharathi Konkena, Kalapu Chakrapani, Harneet Kaur, Angelika Holzinger, Hugh Geaney, Valeria Nicolosi, Micheál D. Scanlon, Jonathan N. Coleman
Abstract
High Resolution Image Download MS PowerPoint Slide Cobalt oxide (Co 3 O 4 )-based nanostructures have the potential as low-cost materials for lithium-ion (Li-ion) and sodium-ion (Na-ion) battery anodes with a theoretical capacity of 890 mAh/g. Here, we demonstrate a novel method for the production of Co 3 O 4 nanoplatelets. This involves the growth of flower-like cobalt oxyhydroxide (CoOOH) nanostructures at a polarized liquid|liquid interface, followed by conversion to flower-like Co 3 O 4 via calcination. Finally, sonication is used to break up the flower-like Co 3 O 4 nanostructures into two-dimensional (2D) nanoplatelets with lateral sizes of 20–100 nm. Nanoplatelets of Co 3 O 4 can be easily mixed with carbon nanotubes to create nanocomposite anodes, which can be used for Li-ion and Na-ion battery anodes without any additional binder or conductive additive. The resultant electrodes display impressive low-rate capacities (at 125 mA/g) of 1108 and 1083 mAh/g, for Li-ion and Na-ion anodes, respectively, and stable cycling ability over >200 cycles. Detailed quantitative rate analysis clearly shows that Li-ion-storing anodes charge roughly five times faster than Na-ion-storing anodes.