Self-assembled sandwich-like NiO film and its application for Li-ion batteries

NiO film with sandwich-like morphology is fabricated on nickel foam by a simple ammonia-evaporation process. Ammonia plays a major role in controlling the final geometry during this template- and surfactant-free synthesis. The obtained NiO film is constructed by regular triangular prisms with side length of 500 nm. Each triangular prism is self-assembled by single crystalline platelets. As an anode for lithium ion battery, this NiO film electrode exhibits high discharge capacity and excellent cycling performance. The reversible capacity of the sandwich-like NiO film sustains 400 mAh g−1 even after 50 cycles at 2 C, much higher than that of the dense NiO film prepared by eletrodeposition (198 mAh g−1). The high rate capability and reversibility of this NiO film can be attributed to its unique sandwich-like architecture.