Electrochemical preparation and evaluation of the supercapacitive performance of MnO2 nanoworms

• MnO2 nanoworms were prepared by pulse cathodic deposition for the first time.
• A specific capacitance of 209 F g−1 was obtained at 1 A g−1.
• Capacity retention of 91.1% was observed after 1000 cycling.

In this work, we report the preparation of MnO2 nanoworms through a facile and low-cost electrochemical followed by heat-treatment approach without using any template or surfactant. The deposition experiments were conducted at a pulse current mode with typical on-time and off-time (ton= 5 s and toff=10 s) and an average current density of 2 mA cm−2 (Ia=2 mA cm−2). The obtained hydroxide deposit was heat treated at 300 °C for 3 h. The products were characterized by XRD, FT-IR and SEM and the results revealed the formation of well-crystallized α,γ-MnO2 with a worm-like texture. The prepared MnO2 was further found to exhibit excellent supercapacitive behaviors, i.e, specific capacitance of 202 F g−1 and 91.1% capacity retention after 1000 cycling.