▎ 摘　　要

NOVELTY - Preparation of sea urchin-like nickel cobaltite/stereo structured graphene microsphere composite material with mesoporous structure involves (i) placing the three-dimensional structured graphene powder in a hydrothermal kettle lined with polytetrafluoroethylene, adding 68 wt.% nitric acid and collecting the precipitate by filtering to obtain hydrophilic three-dimensional graphene powder, (ii) ultrasonically dispersing the hydrophilic three-dimensional graphene powder obtained in step (i) into deionized water to obtain a uniformly dispersed hydrophilic three-dimensional graphene solution (A), (iii) dissolving the cobalt nitrate hexahydrate, nickel nitrate hexahydrate, urea and polyethylene glycol-400 in deionized water to obtain solution (B), (iv) mixing the solution (A) and solution (B) to obtain solution (C), (v) transferring the solution (C) into a hydrothermal kettle lined with polytetrafluoroethylene, and (vi) calcining the precursor (D) in a muffle furnace at 280-360 degrees C. USE - Preparation of sea urchin-like nickel cobaltite/stereo structured graphene microsphere composite used for forming negative electrode material for lithium ion battery and sodium ion battery (all claimed). ADVANTAGE - The method is environmentally-friendly, and enables simple preparation of sea urchin-like nickel cobaltite/stereostructured graphene microsphere composite having excellent electrochemical performance. The battery has excellent discharge capacity of 1403 mAh.g-1. DETAILED DESCRIPTION - Preparation of sea urchin-like nickel cobaltite/stereo structured graphene microsphere composite material with mesoporous structure involves (i) placing the three-dimensional structured graphene powder in a hydrothermal kettle lined with polytetrafluoroethylene, adding 68 wt.% nitric acid, heating hydrothermal kettle at a constant temperature, naturally cooling the hydrothermal kettle to room temperature, collecting the precipitate by filtering to obtain hydrophilic three-dimensional graphene powder at 80-160 degrees C for 10-36 hours and drying the obtained powder at 50-90 degrees C, (ii) ultrasonically dispersing the hydrophilic three-dimensional graphene powder obtained in step (i) into deionized water to obtain a uniformly dispersed hydrophilic three-dimensional graphene solution (A), (iii) dissolving the cobalt nitrate hexahydrate, nickel nitrate hexahydrate, urea and polyethylene glycol-400 in deionized water to obtain solution (B), (iv) mixing the solution (A) and solution (B) to obtain solution (C), (v) transferring the solution (C) into a hydrothermal kettle lined with polytetrafluoroethylene, performing a constant temperature thermal reaction, filtering and washing to obtain the three-dimensional graphene-coated nickel cobaltate precursor (D) at 85-160 degrees C for 4-20 hours, and (vi) calcining the precursor (D) in a muffle furnace at 280-360 degrees C for 1-4 hours. The ratio of three-dimensional graphene to nitric acid in step (i) is 1 g:25-70 mL. The dosage ratio of powder and deionized water in step (ii) is 0.1 g:20-50 mL. The dosage ratio of the nickel nitrate hexahydrate, cobalt nitrate hexahydrate, urea and polyethylene glycol-400 in the step (iii) is 0.003-0.009 mol:0.006-0.018 mol:0.036-0.108 mol:2-4 ml. The ratio of the hydrophilic three-dimensional graphene and nickel cobaltate is 0.1 g:0.3-1.2 g.