In Situ Preparation of ID Co@C Composite Nanorods as Negative Materials for Alkaline Secondary Batteries

摘要

Cobalt-based coordination compounds were successfully prepared via employing nitrilotriacetic acid (NTA) as a complexing agent through a mild surfactant-free solvothermal process. Cobalt ions are linked with the amino group or carboxyl groups of NTA to become one-dimensional nanorods that can be proved by Fourier transform infrared measurement findings. The morphologies of the precursor Co—NTA highly depend on the solvent composition, the reaction time and temperature. The probable growth mechanism has been proposed, After heat treatment, the Co—NTA precursor can be completely converted into Co@C nanorods assembled by numerous core—shell-like Co@C nanoparticles, which preserved the rodlike morphology. The as-prepared Co@C composites display a rodlike morphology with 4μm length and 100 nm diameter, The electrochemical performances of this novel Co@C material as the alkaline secondary Ni/Co battery negative electrode have been systematically researched. The discharge capacity of the Co@C-1 composite electrode can attain 609 mAh g~(-1) and retains about 383.3 mAh g~(-1) after 120 cycles (the discharge current density of 500 mA g~(-1)). The novel material exhibits a high discharge capacity of 610 and 470 mAh g~(-1) at discharge currents of 100 and 1000 mA g~(-1), respectively. This suggests that approximately 77% of the discharge capacity is kept when the discharge current density is increased to 1000 mA g~(-1) (10 times the initial current density of 100 mA g~(-1)). The excellent electrochemical properties could be ascribed to the porous channels of the novel Co(SC materials, which is beneficial to electrolyte difrusion and electrons and ions transportation.