L-Alanine mediated controllable synthesis: Ultrathin Co3O4 nanosheets@Ni foam for high performance supercapacitors

Abstract

In this work, we present a general strategy for the fabrication of ultrathin nanosheets structured transitional metal oxides on Ni foam with the assistance of L-alanine, which highlights the controllable hydrolysis of cobalt-alanine complex under mild hydrothermal conditions. Specially, Co3O4 nanosheets with the thickness of approximately 3 nm and interlamellar spacing of about 1 nm are grown on Ni foam (denoted as Co3O4-ns@NF). The unique configuration favors the deep penetration of electrolyte within electrode matrix and thus enhances the utilization of electroactive Co3O4. As a result, the present Co3O4-ns@NF manifests a high specific capacity of 882 C·g−1 at 2 A·g−1 and excellent stability with 92.9% specific capacity retention after 5000 cycles at elevated current density (20 A·g−1). Moreover, the asymmetric supercapacitor fabricated by electrodes of Co3O4-ns@NF and activated carbon exhibits excellent energy storage abilities, such as high energy and power densities (66.6 Wh·kg−1 at 2250 W·kg−1), high rate capability as well as excellent cycling stability, demonstrating the great potential of the present Co3O4-ns@NF in high performance supercapacitors.