Structural Engineering of Core–Shell Ni<sub>3</sub>B@Ni(BO<sub>2</sub>)<sub>2</sub> on V<sub>2</sub>MoO<sub>8</sub> (0D@2D/1D) Composites: Advanced Strategies for Enhancing High Energy Density in Asymmetric Supercapacitors
Ahamed Milton, Abdullah Al Mahmud, Ramaraj Sukanya, Raj Karthik, Eswaran Kamaraj, Carmel B. Breslin, P. Muhammed Shafi, Jae‐Jin Shim
Abstract
High Resolution Image Download MS PowerPoint Slide The development of hierarchical core–shell structures and multicomponent metal boride/metal oxide-based composites presents a promising strategy to enhance supercapacitor (SC) performance. In this study, we synthesized a Ni 3 B@Ni(BO 2 ) 2 (0D@2D) core–shell structure and integrated it with V 2 MoO 8 (VMO) rods (1D) to form a Ni 3 B@Ni(BO 2 ) 2 /VMO (NB@NBO/VMO (0D@2D/1D)) composite. This composite was then used as an electrode material on a flexible carbon cloth (CC) substrate for SC applications. The 1D-VMO rods were derived from V-doped MoSe 2 nanosheets via hydrothermal synthesis and calcination, while the NB@NBO/VMO composite was obtained by using a liquid-phase method. Structural, compositional, and morphological characterizations were conducted using XRD, XPS, FE-SEM, and TEM-EDS. In a three-electrode system, the NB@NBO/VMO-50 composite showed an impressive C s of 698 F g –1 at 1 A g –1, ascribed to its unique core–shell architecture, which enhances contact and faradaic properties, shortens ion diffusion paths, and provides abundant active sites. Notably, the NB@NBO/VMO-50 displayed excellent cyclic stability, retaining 75.1% of its capacitance after 10,000 cycles at 10 A g –1 . This performance is better than those of other electrodes, including pristine VMO/CC, NB/CC, NB@NBO/VMO-25, and NB@NBO/VMO-75. When evaluated in a two-electrode asymmetric SC system, the NB@NBO/VMO-50/CC||rGO device operated at 1.6 V and delivered a high energy density (ED) of 40.5 Wh kg –1 at a power density (PD) of 800 W kg –1 . It also reached a PD of 16,000 W kg –1 while maintaining an ED of 23.5 Wh kg –1 . The device also showed remarkable long-term durability, maintaining 79.3% of its capacitance and 99.9% Coulombic efficiency after 8000 charge–discharge cycles at 8 A g –1, demonstrating its strong potential for next-generation energy storage applications.