Bamboo-derived carbon induced self-assembly of Mg-modulated Ni–Co layered hydroxide heterostructures for high-performance asymmetric supercapacitors

Abstract

Bamboo is an abundant and fast-growing lignocellulosic resource with considerable potential as a sustainable precursor for functional carbon materials. In this work, bamboo-derived carbon microspheres were employed to induce the self-assembly of Mg-modulated Ni-Co layered hydroxide heterostructures, forming a hierarchical composite electrode denoted as NCM@BC. During synthesis, the carbon microspheres acted not only as conductive supports but also as heterogeneous nucleation sites for hydroxide growth, leading to an open architecture that facilitated electrolyte penetration and charge transport. Meanwhile, Mg incorporation regulated the local coordination environment of the Ni-Co hydroxide phase and improved the structural stability of the layered framework during repeated redox reactions. As a result, the optimized NCM@BC-20 electrode delivered a specific capacitance of 1226.8 F g−1 at 1 A g−1 with favorable rate capability. Furthermore, the assembled asymmetric supercapacitor, using NCM@BC-20 as the positive electrode and activated carbon as the negative electrode, operated over a 1.6 V voltage window, achieved an energy density of 63.16 Wh kg−1 at 800 W kg−1, and retained 89.1% of its peak capacitance after 6000 cycles. These results demonstrate that bamboo biomass can be converted into a value-added carbon component that not only directs heterostructure formation but also contributes to enhanced electrochemical performance, providing a practical route for the development of sustainable carbon-based electrode materials.