Interconnected nickel bicarbonate (Ni(HCO3)2) hollow spheres were produced and exploited for the first time as an anode of lithium ion batteries, delivering the 80th reversible capacity of 1442 mAh g-1 at a current rate of 100 mA g-1, which is 3.9 times the theoretical capacity of commercial anode graphite. The time-dependent study suggested a self-sacrificial templating formation mechanism that yielded intriguing interconnected hollow structures. X-ray photoelectron spectroscopy measurements on cycled electrodes indicated that both the deep oxidation of Ni2+ into Ni3+ and the reversible reactions in HCO3 - accounted for the ultrahigh capacity of Ni(HCO3)2 in comparison to its generally accepted theoretical capacity of 297 mAh g-1. Morphological characterizations revealed that the interconnected hollow structures enabled the enhanced rate performance and cycling stability, compared to those of the solid counterpart, because of their larger contact areas with electrolyte and better buffering effect to accommodate the volume change.
Bibliographical noteFunding Information:
We gratefully acknowledge the financial support from the National Natural Science Foudation of China (21673131), the Taishan Scholar Project of Shandong Province (ts201511004), the Natural Science Foundation of Shandong Province (ZR2016BM03) and Shandong University (2014JC016), and Guangzhou Science Technology and Innovation Commission (2016201604030013). S.Z. acknowledges the financial support from the China Scholarship Council.
© 2016 American Chemical Society.