In situ growth of Cu2+1O/Cu2(CO3)(OH)2/Co(OH)2 with multi-dimensional hybrid structure for high performance flexible supercapacitors

In situ growth of Cu2+1O/Cu2(CO3)(OH)2/Co(OH)2 on carbon cloth (CC) is achieved via a facile wet chemical oxidation strategy combined with hydrothermal method, and the self-supported Cu2+1O/Cu2(CO3)(OH)2/Co (OH)2 displays a unique multi-dimensional hybrid structure. Cu2+1O (CuO with excess metal defects) electroless plated on the surface of CC can not only retain the nanostructures of Cu2(CO3)(OH)2 and Co(OH)2, but also act as the buffer layer to ease volumetric expansion of the materials during the repeated charge/ discharge process. When the CC@Cu2+1O/Cu2(CO3)(OH)2/Co(OH)2 is used in flexible supercapacitors, it ex-hibits significantly enhanced areal specific capacitance (624.5 mF cme2 at 0.5 mA cme2), rate capability (86.6 %), cyclic stability (100.3 % retention after 1500 cycles) and coulombic efficiency (99.3 % retention after 1500 cycles) due to the synergistic effect of Cu2+1O buffer layer, two-dimensional (2D) Co(OH)2 nanosheets and three-dimensional (3D) Cu2(CO3)(OH)2 nanoblocks. (c) 2023 Elsevier B.V. All rights reserved.