3D LiCoO2 nanosheets assembled nanorod arrays via confined dissolution-recrystallization for advanced aqueous lithium-ion batteries

Three-dimensional (3D) electrodes with freestanding feature represent the state-of-art electrode design for advanced lithium-ion batteries. Construction of 3D architectures for cathode materials, however, is still a great challenge. In this work, freestanding 3D LiCoO2 nanosheets assembled nanorod arrays are grown on carbon fabric via confined dissolution-recrystallization on the Co(CO3)(1-x)(OH)(2x)center dot nH(2)O nanowire arrays during hydrothermal treatment. The formed intermediate CoOOH nanosheets can catalyze the decomposition of H2O2 and the generated continuous oxygen bubble layer enables self-limiting dissolution-recrystallization. After final heat treatment at a low temperature of 380 degrees C, the obtained 3D hierarchy LiCoO2 nanorod arrays exhibit large specific capacity, excellent rate performance, and outstanding cycling stability when tested as cathode for aqueous lithium-ion batteries. It is found that the hydrothermally synthesized LiCoO2 sample without heat treatment still has some structure distortion with proton intercalation and Li+ occupancy at abnormal sites, which deteriorate its electrochemical performance. By using the 3D hierarchy LiCoO2 nanorod arrays as cathode, a flexible aqueous LiCoO2//LiTi2(PO4)(3) lithium-ion battery device is successfully constructed, demonstrating superior rate performance and cycle performance.