Elucidation of reaction mechanisms of Ni2SnP in Li-ion and Na-ion systems

作者：Marino C^*; Dupre N; Villevieille C^*

来源：Journal of Power Sources, 2017, 365: 339-347.

DOI：10.1016/.i.jpowsour.2017.08.096

• Negative electrode
• Na-ion battery
• Li-ion battery
• Conversion material
• X-ray absorption spectroscopy
• NMR spectroscopy

Electrochemical performance of Ni2SnP was assessed in Li-ion and Na-ion battery systems. When cycled versus Li, Ni2SnP exhibited a reversible specific charge of 700 mAh.g(-1) (theoretical specific charge: 742 mAh.g(-1)). In the Na system, the specific observed charge was ca. 200 mAh.g(-1) (theoretical specific charge: 676 mAh.g(-1)). X-ray diffraction, Ni K-edge X-ray absorption spectroscopy, and P-31 and Li-7/Na-23 nuclear magnetic resonance spectroscopy were used to elucidate the electrochemical mechanisms in both systems. Versus Li, Ni2SnP undergoes a conversion reaction resulting in the extrusion of Ni and the alloying of Li-Sn and Li-P. On delithiation, the material partially recombines into a Sn- and Ni-deficient form. In the Na system, Ni2SnP reacts through the conversion of P into Na3P. These results indicate that the recombination of the pristine material (even partially) increases cycling stability.

• 出版日期2017-10-15