Facile synthesis of TiP 2 O 7 /C nanoparticles as a competitive anode for aqueous lithium ion batteries

TiP2O7 is an applicable anode for aqueous Li ion batteries (ALIBs) for its suitable potential and competitive capacity. However, inferior cycling performance and rate capability owing to the poor ionic and electronic conductivities have greatly restricted its application in ALIBs. To tackle these issues, the strategies of nanostructuring and high quality carbon coating were developed in this work. TiP2O7/C nanoparticles with a size of ca. 50 nm have a high surface area of 41.07 m2 g−1. In this composite, TiP2O7 nanoparticle is well coated by a uniform carbon layer (thickness of ca. 10 nm and carbon content of 7.65 wt%). The as-obtained TiP2O7/C composite shows an excellent cycling performance (90.6% capacity retention after 100 cycles at 30 mA g−1 and 97.3% capacity retention after 600 cycles at 750 mA g−1) and superior rate capability (97 mAh g−1 at 30 mA g−1 and 78 mAh g−1 at 300 mA g−1). It is found that the intrinsically stable structure of TiP2O7 nanoparticles and the uniform carbon coating greatly contributed to their superior electrochemical properties in aqueous electrolyte.