context: The UTCNF cathode was prepared via a simple and efficient ultrasonic-treatment strategy. In detail, a piece of pre-cleaned CNF (1 cm × 3 cm × 0.15 cm), thoroughly washed with acetone and water, was immersed in 3 M HCl. Next, the solution was transferred to an ultrasonic apparatus and ultrasonicated for 10 min. After the ultrasonic treatment, the CNF was rinsed with distilled water twice and dried at 60 °C to obtain the UTCNF. The mass loading of the cobalt/nickel composite hydroxide, obtained by comparison of the weight change between UTCNF and CNF, is ∼6.0 mg cm−2.
answer: UTCNF 