To improve overall electrochemical performance, we report and propose zinc cobaltite (ZnCo2O4) nanowire arrays with a simple and precisely controllable NH3 plasma treatment. The NH3 plasma treatment effectively changes the electronic and chemical properties of the pristine ZnCo2O4 by the nitrogen doping and surface functionalization simultaneously. By way of the nanoscale surface/electrical modification of ZnCo2O4, the nitrogen (N)-doped ZnCo2O4 electrodes not only significantly enhanced the electrical conductivity but also increased the density of the hydroxyl group by appropriately controlling the Co2+/Co3+ ratio (oxygen vacancies). Compared to pristine ZnCo2O4 (1682.2 F g-1 at 5 A g-1), the N-doped ZnCo2O4 electrode without conductive additives possessed high specific capacitance (3804.6 F g-1 at 5 A g-1), excellent rate capability (95.45% capacity retention at 40 A g-1), and good cycling stability (only 3.3% loss after 3000 cycles at 30 A g-1). These nanoscale surface state engineering methods may open a new avenue to optimize electrochemical performance for energy storage and conversion.
Bibliographical noteFunding Information:
This research was supported by the Ministry of Science, ICT and Future Planning (MSIP), Korea, under the “IT Consilience Creative Program” (IITP-2018-2017-0-01015) supervised by the Institute for Information & Communications Technology Promotion (IITP). This research was supported by Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education (NRF-2018R1D1A1B07045703).
Copyright © 2018 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Chemical Engineering (miscellaneous)
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering
- Materials Chemistry