Mesoporous TiNb2O7 nanosheets anode with excellent rate capability and cycling performance in lithium ion half/full batteries

The Wadsley-Roth phase TiNb2O7 has attracted considerable attention because of its high intercalation potential and excellent cycle capability. However, the poor electronic conductivity and sluggish ionic diffusion kinetics hinder its commercial application. Herein, a novel mesoporous TiNb2O7 nanosheet (MS-TNO) is fabricated via solvothermal and subsequent calcination process. Two-dimensional mesoporous nanostructures can effectively shorten transport path of lithium ions and enhance charge transfer. Galvanostatic intermittent titration technique (GITT) test shows the values of Li+ diffusion coefficient during discharge/charge vary in range of 10−12–10−11 cm2 S−1, indicating high efficient Li+ diffusion pathways in the lattice. In situ X-ray diffraction experiment elucidates the insertion/extraction of Li+ in MS-TNO is highly reversible, with a unit-cell volume change of 7.22% after Li+ insertion. Consequently, MS-TNO material delivers significant surface-controlled capacitive behavior and excellent electrochemical performances. These results clearly demonstrate that the MS-TNO is a promising anode material for rapid-charging, high capacity, safe and stable lithium ion batteries.