Performance and Mechanism of Negative Electrodes Based on p-Group Elements for Na Batteries

Na-based storage systems working at ambient temperature have recently regained interest. Even though most recent research on Na-ion systems has concentrated on the development of positive electrode materials, several works have appeared on negative electrode materials, mostly based on the insertion of Na into hard carbon structures developing a capacity as high as ~300 mAh/g.[1, 2] However, the large ionic radius of Na⁺ with respect to Li⁺leads to a higher volume expansion upon cycling, which is expected to strongly affect insertion reactions as well as alloying or conversion reactions. Surprisingly Sn- and Sb-based electrodes recently showed to be a viable alternative to hard carbon, providing very interesting performances with reversible capacities largely exceeding 400 mAh/g.[3-5]

Starting from our expertise in alloys electrode materials for LiB, we have investigated several phases containing P, Sb and/or Sn as electrode materials for Na batteries. Electrodes based on bare commercial antimony or on ball milled SnSb can sustain over 150 cycles at C/2 vs. Na without any capacity fading.[6-7] Recently we demonstrated that phosphides show also promising electrochemical features in Na batteries.[8]

The thorough investigation of both mechanism and performances of these systems will be presented. The good electrochemical performances of such electrode materials are very surprising if one take into account the huge volume expansion expected from the reaction with Na (200-400 %). Moreover, this investigation reveals intriguing reaction mechanisms, differing from those commonly observed in analogous Li-ion systems and not always corresponding to those expected from the known equilibrium phase diagrams of Na-Sn, Na-Sb or Na-P.

References:

1.  S. Komaba, W. Murata, T. Ishikawa, N. Yabuuchi, T. Ozeki, T. Nakayama, A. Ogata, K. Gotoh, K. Fujiwara, Adv. Funct. Mater., 21 (2011) 3859

2. A. Ponrouch, A.R. Goñi, M. Rosa Palacín, Electrochem. Comm., 27 (2013) 85

3. L. Xiao, Y. Cao, J. Xiao, W. Wang, L. Kovarik, Z. Nie, J. Liu, Chem. Commun., 48 (2012) 3321

4. J. Qian, Y. Chen, L. Wu, Y. Cao, X. Ai, H. Yang, Chem. Commun., 48 (2012) 7070

5. S. Komaba, Y. Matsuura, T. Ishikawa, N. Yabuuchi, W. Murata, S. Kuze, Electrochem. Comm., 21 (2012) 65

6. A. Darwiche, C. Marino, M.T. Sougrati, B. Fraisse, L. Stievano, L. Monconduit, J. Am. Chem. Soc., 134 (2012) 20805

7.  A. Darwiche, M. T. Sougrati, B. Fraisse, L. Stievano, L. Monconduit Electrochem. Comm., (2013)  18–21

8.  J.Fullenwarth, A. Darwiche, A. Soares, B. Donnadieu,  L. Monconduit  accepted  at  J. Mat. Chem. (2013), DOI:10.1039/C3TA13976J