LiMn₂O₄ nanorod arrays: A potential three-dimensional cathode for lithium-ion microbatteries

Highlights: • Self-supported LiMn₂O₄ nanorod arrays are prepared on the Pt substrates. • LiMn₂O₄ nanorod array cathode exhibits a large areal capacity of 0.25 mAh cm⁻². • LiMn₂O₄ nanorod array cathode exhibits good cycle performance and rate capability. • LiMn₂O₄ nanorod arrays are potential cathodes for 3D microbatteries. - Abstract: Although three-dimensional (3D) microbatteries represent great advantage compared to their two-dimensional counterparts, the fabrication of 3D cathode is still a challenge, which holds back the further development of 3D microbatteries. In this work, we present a novel approach for fabrication of LiMn₂O₄ nanorod arrays as 3D cathode for microbatteries. α-MnO₂ nanotube arrays are firstly grown on the Pt substrate as the template, and LiMn₂O₄ nanorod arrays are then prepared by lithiation of α-MnO₂ nanotube arrays in molten salt followed by 800 °C annealing in air. In the half cell test, the 3D LiMn₂O₄ nanorod arrays exhibit both high gravimetric capacity (∼130 mAh g⁻¹) and areal capacity (∼0.25 mAh cm⁻²), while maintaining good cycling stability and rate capability. The facile synthesis and superior electrochemical performance of the three-dimensional LiMn₂O₄ cathode make it promising for application in microbatteries