Synthesis of Anatase TiO₂ Nanosheets with\nEnhanced Pseudocapacitive Contribution for Fast Lithium Storage

Abstract

Anatase TiO₂ nanosheets\n(ATNs) are successfully prepared by a biomimetic layer-by-layer titania\nmineralization approach, and the electrochemical performance of the\nATNs as negative electrode for lithium-ion batteries is investigated\nby the galvanostatic chronopotentiometry and cyclic voltammetry. A\nhigh initial discharge capacity (311 mA h g^–1) and\ninitial Coulombic efficiency (81.7%) were obtained for ATNs, and capacities\nof 252, 202, 186, 158, 136, and 119 mA h g^–1 were\nobtained at 0.2, 1, 5, 10, 20, and 30 C, respectively. Particularly,\nthe ATNs can still maintains a capacity of 108 mA h g^–1 after 4000 cycles at 30 C (only a capacity loss of 10%), which indicated\na superior rate capabilities and cyclability. The CVs analysis revealed\nthat the ANTs have both diffusive lithium storage in the bulk and\npseudocapacitive lithium storage at the surface (also called interfacial\nlithium storage), and the pseudocapacitive lithium storage dominates\nthe total capacity when the scan rates are above 1 mV s^–1. The fast and stable lithium storage of ATNs might be attributed\nto the high pseudocapacitive lithium storage contribution in the material,\nand it was suggested the pseudocapacitive lithium storage could occurred\nat grain–grain interfaces as well as nanosheet surfaces.