3D nanocomposite archiecture constructed by reduced graphene oxide, thermally-treated protein and mesoporous NaTi2(PO4)3 nanocrystals as free-standing electrodes for advanced sodium ion battery
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NaTi2(PO4)3 (NTP) with NASICON structure has been regarded as a promising material for sodium-ion batteries (SIBs). However, NTP always exhibits poor cycling stability and rate performance due to slow electronic conductivity. In this work, a free-standing 3D nanocomposite constructed by reduced graphene oxide (rGO), thermally-treated protein (TP) and mesoporous NaTi2(PO4)3 nanocrystals (denoted as MNTP-TP@rGO) is reported. The fabrication includes an electrostatic self-assembly, freeze-drying, mechanical pressing and thermal treatment. In the MNTP-TP@rGO nanocomposite, 3D interconnected carbon network of rGO and TP acts as both a support for the anchored well-distributed MNTP nanocrystals and a current collector. When free-standing MNTP-TP@rGO is used directly as anode in coin-type half-cell, it delivers a high-rate capacity (52.8 mAhg−1 at 50C) and robust cycling stability with the capacity retention of 80% after 1000 cycles at 5C. Furthermore, a full Na-ion battery is constructed using Na3V2(PO4)3/C (NVP/C) as a cathode and free-standing MNTP-TP@rGO as an anode and it exhibits a high specific capacity (58 mAhg−1 at 1C) and outstanding cycling stability (98% capacity retention over 100 cycles at 1C). Our results suggest great potential of the free-standing electrode of MNTP-TP@rGO composite in high-performance SIBs.
This work was financially supported by the Grants from National Natural Science Foundation of China (Nos. 11474242, 51472209 and 11774298) and the Hunan Provincial Innovation Foundation for Graduate (No. CX2016B254).