Facile synthesis of porous NiO hollow microspheres and its electrochemical lithium-storage performance

► Porous NiO hollow microspheres are fabricated. ► Each microsphere consists of many nanoparticles of 30-80 nm. ► The synthesis involves an ultrasound-assisted route followed by thermal annealing. ► The microspheres show enhanced lithium-storage performance due to porous architecture.