NbyW1-yOz and NbxTi1-xOz pseudobinaries as anodes for Li-ion batteries

Although high energy density Li-ion batteries are a high priority for electric vehicles, there is also an important demand for safe high power batteries for various applications including medical devices. In such applications, the state-of-the-art anode is Li4Ti5O12 (LTO) with limited capacities. Herein, we utilize a high-throughput approach to study compositions of Nb-based anodes in two pseudobinary systems: NbyW1-yOz and NbxTi1-xOz as potential high capacity replacements for LTO. All samples are characterized by both X-ray diffraction and electrochemistry in high-throughput. The resulting phase stabilities are presented and show significant solid solution regions that have never been explored before. The resulting electrochemical data show that numerous compositions (particularly for Nb metal fraction above 50%) show excellent performance with capacities over 200 mAh/g, very good rate performance (e.g. >80% capacities when the CV sweep rate is increased by an order of magni-tude) and diffusion constants greater than 10-6 cm2 s- 1 in high loading electrodes (about 20 mg/cm2). This study represents a first precise screening of battery performance across these two binaries of high current interest and permits a deepening of our understanding of the structure-property relations in these important systems.

Automated summary

In this study, compositions of Nb-based anodes in two pseudobinary systems (NbyW1-yOz and NbxTi1-xOz) were investigated using a high-throughput approach as potential high capacity replacements for Li4Ti5O12. The samples were characterized by both X-ray diffraction and electrochemistry, revealing significant solid solution regions that have not been explored before. The resulting electrochemical data showed excellent performance of many compositions, with capacities over 200 mAh/g, good rate performance, and high diffusion constants, providing a deepening of our understanding of the structure-property relations in these important systems.