Layered H2Ti6O13-Nanowires: A New Promising Pseudocapacitive Material in Non-Aqueous Electrolyte

Layered H2Ti6O13-nanowires are prepared using a facile hydrothermal method and their Li-storage behavior is investigated in non-aqueous electrolyte. The achieved results demonstrate the pseudocapacitive characteristic of Li-storage in the layered H2Ti6O13-nanowires, which is because of the typical nanosize and expanded interlayer space. The as-prepared H2Ti6O13-nanowires have a high capacitance of 828 F g-1 within the potential window from 2.0 to 1.0 V (vs. Li/Li+). An asymmetric supercapacitor with high energy density is developed successfully using H2Ti6O13-nanowires as a negative electrode and ordered mesoporous carbon (CMK-3) as a positive electrode in organic electrolyte. The asymmetric supercapacitor can be cycled reversibly in the voltage range of 1 to 3.5 V and exhibits maximum energy density of 90 Wh kg-1, which is calculated based on the mass of electrode active materials. This achieved energy density is much higher than previous reports. Additionally, H2Ti6O13//CMK-3 asymmetric supercapacitor displays the highest average power density of 11 000 W kg-1. These results indicate that the H2Ti6O13//CMK-3 asymmetric supercapacitor should be a promising device for fast energy storage.