Hierarchical Fusiform Microrods Constructed by Parallelly Arranged Nanoplatelets of LiCoO₂ Material with Ultrahigh Rate Performance

The past few decades have witnessed the unprecedented success of the commercialized LiCoO₂ layered cathode in consumer electronics, but it still faces the poor rate capability and cycling performance because of its hexagonal layered α-NaFeO₂ structure and the high energy of electrochemically active crystal planes. In a bid to address these problems, we report the delicate design and synthesis of hierarchical fusiform LiCoO₂ microrods constructed by directionally assembled nanoplatelets along the [001] direction via a self-template route (PAHF-LCO). Remarkably, it is the first time that almost all the exposed surfaces of layered cathodes are dominated by the consistent {010} facets, which enable the express channels of Li⁺ diffusion to penetrate throughout the entire fusiform microrods. The as-obtained PAHF-LCO cathode material delivers specific capacities of 113 and 106 mA h g^–1 at 10 and 20 C after 200 cycles, respectively. Even under the high rate of 50 C, the discharge capacity initializes around 105 mA h g^–1 and ends around 80 mA h g^–1 after 200 cycles. The improvement mechanisms to the high-rate performance through crystal habit tuning have also been unraveled. The enhanced electrochemical performance can be attributed to the hierarchical fusiform structure as well as the coordinated crystal orientation of {010} facets.