Oxygen vacancies were introduced into TNAs and MnCo2O4/TNAs by direct reduction in NaBH4 solution. Reduced TNAs exhibited the highest specific capacitance of 23.24 mF cm−2 and excellent long term cycling stability. A remarkable specific capacitance of 484.35 mF cm−2 was achieved from the MnCo2O4/TNAs treated in NaBH4 solution.