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Three-dimensional (3D) multicolor NiMn LDH nanoparticles are produced without the need of a substrate by using a one-step N source-assisted hydrothermal reaction and various Mn ratios, resulting in a variety of hues. Their physical features and architectures disclose their intriguing electrochemical capabilities, resulting in improved rate performance throughout the electrochemical process. [Display omitted] • A facile strategy was proposed to synthesis fascinating 3D multicolor NiMn LDH. • NiMn LDH polychromatic phenomenon in which the content of Mn element plays a key role. • NiMn LDH was grown on porous carbon to enhance the electrochemical performance of LDH. • The as-synthesized NiMn LDH /F-AC demonstrate excellent capacity at high current. Layered Double Hydroxide (LDH), as a typical two-dimensional electrochemical storage material, has shown great potential in the field of supercapacitors. Herein, three-dimensional (3D) multicolour NiMn LDH nanoparticles were prepared without substrate using a one-step formula using different levels of Mn and various N sources to assist the hydrothermal reaction. The appearance of the designed materials expressing different colors is owing to the Mn content of the reference playing an important role, where the electrochemical performance and structural stability also become more prominent. Adding a suitable Mn content to the G-NiMn LDH maintains the structural integrity and ultra-flake-like structure, revealing a uniform size of 2 μm compared with B-NiMn LDH. It provides abundant redox sites, enabling the green LDH to exhibit excellent electrochemical performance in appearance (1108 F g−1@1 A g−1 in G-NiMn LDH). Furthermore, the in-situ growth of G-NiMn LDH nanomaterials (denoted as G-NiMn LDH/F-AC) on F-doped activated carbon material (F-AC) brought increased active sites, effectively inhibited the accumulation of nanosheets, revealing a good rate capability (78 %@15 A g−1). Moreover, the asymmetric supercapacitor's positive and negative electrodes are G-NiMn LDH/F-AC and biomass carbon, up to 73 F g−1. This study methodology offers a novel viewpoint on the manufacture and discussion of LDH for understanding electrode materials' structural and surface chemical characteristics. [ABSTRACT FROM AUTHOR]

Transition metal sulfides (TMSs) are utilized in supercapacitors as electrode materials for their high theoretical capacity. The fabrication of TMSs/carbon composite for supercapacitors has gained much interest because of its favorable electron conductivity, and mechanical strength. Herein, the biomass absorption method is applied to fabricate NiS/Ni 3 S 4 carbon composite. Carbon-wrapped nickel (Ni@C) is obtained through the carbonization of Ni2+ absorbed biomass. The wrapping structure can prevent nanoparticles from stacking and structure collapse. In the following process, utilizing Na 2 SO 4 as activator and sulfur source, it etches the carbon surface to create multistage pore structure, and meanwhile, the carbon matrix reduced part of SO 4 2- to form S2-/S that can be captured by the available active sites, leading to produce S-S/C-S bond. Subsequently, A-NiS/Ni 3 S 4 @C and NiS/Ni 3 S 4 @C were effectively obtained after sulfuring A-Ni@C and Ni@C in the condition of hydrothermal, respectively. Benefitting from the bonding structure and coating characteristics, A-NiS/Ni 3 S 4 @C presented better ion diffusion behavior and exhibited a specific capacity of 560.6 F g−1 at 1 A g−1, F g−1 higher than that of NiS/Ni 3 S 4 @C. Furthermore, the A-NiS/Ni 3 S 4 @C was also assembled into a hybrid supercapacitor and showed a specific capacity of 118.6 F g−1 at 1 A g−1. • Biomass-derived carbon well confined NiS/Ni 3 S 4 nanoparticles was successfully prepared. • Nanoparticles can be obtained efficiently via biomass absorption method. • Na 2 SO 4 can enhance the property in a mild way by etching the carbon surface physically and form C-S/S-S. • Offering a new method for the fabrication of nanocomposite and mild way for polish the properties of carbon. [ABSTRACT FROM AUTHOR]