Ultrathin mesoporous shell Co3O4 hollow spheres as high-performance electrode materials for lithium-ion batteries

Abstract

Ultrathin mesoporous shell Co3O4 hollow spheres (T-CO) as nanostructured anode materials for lithium-ion batteries are synthesized using carbon sphere@Co-glycolate via a solvothermal reaction, followed by calcination process of 400 °C at a heating rate of 2 °C min−1. T-CO is composed of ultrathin shell of ∼45 nm thickness with highly mesoporous morphology and wide void of ∼700 nm distance with vastly macroporous morphology, leading to superior electrochemical performance. T-CO delivers outstanding specific capacity of 1612 mA h g−1 at the 200th cycle at a high current density of 1.5 A g−1 without any apparent capacity fading. Moreover, with the increase in 10 cycles, T-CO delivers 1560, 1620, 1650, 1640, 1460, 1010, and 635 mA h g−1 at the various current densities of 0.5, 1, 1.5, 2.5, 5, 8 and 10 A g−1, and then still maintains around 1320 mA h g−1 at 1.5 A g−1 at the 90th cycle. The reasons for showing superior electrochemical performance are as follows: (i) ultrathin mesoporous shell and wide void facilitating the redox reaction, (ii) ultrathin shell with highly mesoporous morphology increasing electrochemical sites, and (iii) wide void accommodating severe volume change and storing electrolyte for facile mass transfer; thereby maintaining the morphological integrity.