Fig. 1.
TM-HEO particles and their specific capacities. a SEM micrograph of the as-synthesized TM-HEO powder with typical particle sizes from the nano-to-micrometer range. The inset shows that the powder contains both hollow and filled spheres. The scalebars shown in a and the inset correspond to 2 µm and 1 µm, respectively. b Galvanostatic rate capability test (current values given in units of A g‒1). The capacity decreases as the specific current is increased stepwise up to 3 A g‒1, but it recovers at 0.1 A g‒1 and even increases after 100 cycles to 770 mAh g‒1. c Long-term cycling performance at 0.2 A g‒1