Cobalt Oxide Grown on Biomass Carbon as a Three‐Dimensional Self‐Supporting Negative Electrode with High Area Specific Capacity.

The development of electronic equipment and electric vehicles fields has brought enormous challenges to the energy storage sector. Electrode cost has become the biggest problem for large‐scale applications of lithium‐ion batteries. Herein, we use carbonized hemp rods as a current collector instead of expensive copper foil. Meanwhile, the three‐dimensional (3D) structure of carbonized hemp stalk (C‐hemp) has a large number of hollow channels, in which a large amount of Co3O4 nanowires are grown, providing an area specific capacity of 10 mAh/cm2. The battery exhibits a good cycle performance and keeps a stable capacity during 50 charge‐discharge cycles. At the same time, the carbon matrix provides an excellent 3D conductive network that combines with metal oxide nanorods to show an excellent rate performance. [ABSTRACT FROM AUTHOR]