Morphology-Dependent Li Storage Performance of OrderedMesoporous Carbon as Anode Material.

Rod-shapedordered mesoporous carbons (OMCs) with different lengths,prepared by replication method using the corresponding size-tunableSBA-15 silicas with the same rodlike morphology as templates, areexplored as anode material for Li-ion battery. All of the as-synthesizedOMCs exhibit much higher Li storage capacity and better cyclabilityalong with comparable rate capability as compared with commercialgraphite. Particularly, the OMC-3 with the shortest length demonstratesthe highest reversible discharge capacity of 1012 mAh g–1at 100 mA g–1and better cyclability with 86.6%retention of initial capacity after 100 cycles. Although the Coulombicefficiencies of all the OMCs are relatively low at the beginning,they improve promptly and after 10 cycles reach the level comparableto commercial graphite. Based on their specific capacity, cycle efficiency,and rate capability, the OMC-3 outperforms considerably its carbonpeers, OMC-1 and OMC-2 with longer length. This behavior is mainlyattributed to higher specific surface area, which provides more activesites for Li adsorption and storage along with the larger mesoporevolume and shorter mesopore channels, which facilitate fast Li iondiffusion and electrolyte transport. The enhancement in reversibleLi storage performance with decrease in the channel length is alsosupported by low solid electrolyte interphase resistance, contactresistance, and Warburg impedance in electrochemical impedance spectroscopy. [ABSTRACT FROM AUTHOR]