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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]

Polydopamine modified reduced graphene oxides (PDA‐rGO) are synthesized by a facile dopamine polymerization reaction. As‐prepared PDA‐rGO shows a capable electrochemical performance as an electrode material for supercapacitors. A capacitance of 120 F g−1 is achieved at current density of 2 A g−1. PDA‐rGO also presents a superior cycling performance with capacitance retention of ∼99% after 10000 cycles. The remarkable electrochemical performance is attributed to the addition of PDA, which prevents the stacking of rGO and enhances the wettability of composite. Meanwhile, the rGO with high conductivity promise fast electronic transport. Polydopamine modified reduced graphene oxides (PDA‐rGO) are synthesized by a facile dopamine polymerization reaction. A capacitance of 120 F g−1 is achieved at current density of 2 A g−1. PDA‐rGO also presents a superior cycling performance with capacitance retention of ∼99% after 10000 cycles. The remarkable electrochemical performance is attributed to the addition of PDA, which prevents the stacking of rGO and enhances the wettability of composite. [ABSTRACT FROM AUTHOR]