No abstract

It is necessary to design an anode material for lithium-ion batteries (LIBs) with good lithium storage capacity. In the present work, the CNTs@PDA/CoMoS4 composite materials were prepared through self-polymerization of dopamine (PDA) and coating on carbon nanotubes and then deposition of CoMoS4 by a hydrothermal method. Benefited from the formation of the coordination bond between the hydroxyl groups of PDA and the metal ions of CoMoS4, the combination between the CNTs@PDA matrix and CoMoS4 nanoparticles is effectively enhanced. As a result, CoMoS4 nanoparticles grow uniformly on the surface of CNTs@PDA, which reduces the diffusion length of Li+ and improves the electronic transmission efficiency. The CNTs@PDA/CoMoS4 as an anode material exhibits outstanding electrochemical properties in terms of a high capacity of 1025.2 mA h·g–1 after 100 cycles at 0.1 A·g–1. Meanwhile, its capacity is 490.3 mA h·g–1 after 200 cycles at 1 A·g–1. The desirable electrochemical properties combined with the stable structure and the facile synthesis route make CNTs@PDA/CoMoS4 composites a potential candidate for high-performance LIBs.

A novel activated nitrogen‐doped hierarchically porous carbon (ANPC) material has been synthesized using polyurethane foam as the supporting template, phenolic resin with a high carbonization ratio, and low‐cost ammonium polyphosphate as the carbon and nitrogen sources, respectively. The preparation process comprises curing and carbonization combined with KOH activation. Despite the simplicity of the process, the obtained ANPC‐4 exhibits a high specific surface area (1452 m2 g−1), a well‐developed specific pore volume (0.799 cm3 g−1), moderate mesoporous content (32.7%), good electrolyte ions transport property, and appropriate nitrogen dopant content. When used as a material for fabricating supercapacitor electrodes, the ANPC‐4 exhibits a significantly high capacitance value of 356 F g−1 at 0.2 A g−1 in a 6 M KOH electrolyte with outstanding rate performance. In addition, the symmetrical capacitors assembled by ANPC‐4 have good specific capacitance (175 F g−1 at 0.2 A g−1), high energy density up to 24.3 Wh kg−1, and good cycling stability (94.5% capacitance retention after 10 000 cycles of testing).