Wuquan Ye

K2Nb8O21 nanotubes with superior electrochemical performance for ultrastable lithium storage

High-performance lithium-ion batteries are important for developing sustainable energy. However, there is a shortage of advanced energy storage materials. K2Nb8O21 is a novel material for lithium storage which has not been investigated systematically. In this work, K2Nb8O21 nanotubes and microtubes were prepared facilely using electrospinning under different conditions. As an anode host, K2Nb8O21 nanotubes showed better long-term cycling, superior rate performance, and higher structural stability compared with microtubes. Electrochemical results showed that K2Nb8O21 nanotubes delivered a considerable lithium storage capacity of 213 mA h g−1 after 5000 cycles at 1000 mA g−1 with outstanding capacity retention of 80.3%. The nano/micro structured host could increase Li-ion transport to render high-rate capability and excellent cycling stability. In situ XRD, ex situ XPS and ex situ TEM revealed K2Nb8O21 nanotubes had high structural stability and reversibility as lithium storage anode materials. All of these advantages suggest that K2Nb8O21 nanotubes may be promising anode material for lithium-ion batteries.

Sol–Gel Synthesis and in Situ X-ray Diffraction Study of Li3Nd3W2O12 as a Lithium Container

In this work, garnet-framework Li3Nd3W2O12 as a novel insertion-type anode material has been prepared via a facile sol-gel method and examined as a lithium container for lithium ion batteries (LIBs). Li3Nd3W2O12 shows a charge capacity of 225 mA h g-1 at 50 mA g-1, and with the current density increasing up to 500 mA g-1, the charge capacity can still be maintained at 186 mA h g-1. After cycling at 500 mA g-1 for 500 cycles, Li3Nd3W2O12 retains about 85% of its first charge capacity changed from 190.2 to 161 mA h g-1. Furthermore, in situ X-ray diffraction technique is adopted for the understanding of the insertion/extraction mechanism of Li3Nd3W2O12. The full-cell configuration LiFePO4/Li3Nd3W2O12 is also assembled to evaluate the potential of Li3Nd3W2O12 for practical application. These results show that Li3Nd3W2O12 is such a promising anode material for LIBs with excellent electrochemical performance and stable structure.