Microstructure of Li_1+xMn_2–xO₄ spinels obtained from metal-organic precursors

Abstract

A metal-organic precursor method was adopted for the preparation of lithium-manganese spinel oxides. EPR spectra of Mn²⁺ in solutions and in freeze-dried compositions, as well as IR and DSC of freeze-dried compositions, show that α-hydroxyorganic acids (such as lactic, malic and citric acids) chelate Mn²⁺via hydroxy and carboxylate groups. At 450 °C, thermal decomposition of Li-Mn-organic acid precursors with Li/Mn=1.05/1.95 leads to the formation of non-stoichiometric Li[Li_yMn_2–y–Δ□_Δ]O₄ spinels (0.03<y<0.05; 0.02<δ<0.05). EPR of Mn⁴⁺ was used to throw light on the microstructure of the spinels obtained. For the annealed spinels at 750 °C there is a transition from uniform to non-uniform distribution of the excess Mn⁴⁺ ions and the corresponding metal vacancies. As a result, the bulk of the spinel becomes close to the stoichiometric composition Li[Li_0.05Mn_1.95]O₄, whereas the spinel surface accommodates the excess Mn⁴⁺ ions. The formation of Mn⁴⁺-rich surface regions depends both on the cooling rate and on the organic acid used in the precursors. Lactate precursors are most appropriate for the preparation of lithium-manganese spinels with a homogeneous cation distribution.

References

1. M. M. Thackeray, Prog. Batteries Batteries Mater., 1992, 11, 150.
2. R. Koksbang, J. Barker, H. Shi and M. Y. Saïdi, Solid State Ionics, 1996, 84, 1.
3. P. G. Bruce, Chem. Commun., 1997, 1817.
4. J. M. Tarascon, US Pat., 1996, 6, 295.
5. R. J. Gummow, A. de Kock and M. M. Thackeray, Solid State Ionics, 1994, 69, 59.
6. J. M. Tarascon, W. R. McKinnon, F. Coowar, T. N. Bowmer, G. Amatucci and D. Guyomard, J. Electrochem. Soc., 1994, 141, 1421.
7. Y. Gao and J. R. Dahn, J. Electrochem. Soc., 1996, 143, 100.
8. D. G. Wickham and W. Groft, J. Phys. Chem. Solids, 1958, 7, 351.
9. F. le Cras, P. Strobel, M. Anne, D. Bloch, J.-B. Soupart and J.-C. Rousche, Eur. J. Solid State Chem., 1996, 33, 67.
10. M. M. Thackeray, A. de Kock and W. I. F. David, Mater. Res. Bull., 1993, 28, 1041.
11. T. Takada, H. Hayakawa and E. Akiba, J. Solid State Chem., 1995, 115, 420.
12. A. de Kock, M. H. Rossouw, L. A. de Picciotto, M. M. Thackeray, W. I. F. David and R. M. Ibberson, Mater. Res. Bull., 1990, 25, 657.
13. A. Yamada, K. Miura, K. Hinokuma and M. Tanaka, J. Electrochem. Soc., 1995, 142, 2149.
14. J. Sugiyama, T. Atsumi, T. Hioki, S. Noda and N. Kamegashira, J. Alloys Compd., 1996, 235, 163.
15. M. M. Thackeray, J. Electrochem. Soc., 1997, 144, L100.
16. M. M. Thackeray, Y. Shao-Horn, A. J. Kahaiana, K. D. Kepler, E. Skinner, J. T. Vaughey and S. A. Hackney, Electrochem. Solid-35 State Lett., 1998, 1, 7.
17. P. Barboux, J. M. Tarascon and F. K. Shokoohi, J. Solid State Chem., 1991, 94, 185.
18. P. G. Bruce, Phil. Trans. R. Soc. London Sect. A, 1996, 1577.
19. T. Tsumura, S. Kishi, H. Konno, A. Shimizu and M. Inagaki, Thermochim. Acta, 1996, 278, 135.
20. T. Tsumura, A. Shimizu and M. Inagaki, J. Mater. Chem., 1993, 3, 995.
21. S. R. S. Prabaharan, M. S. Michael, T. P. Kumar, A. Mani, K. Athinarayanaswamy and R. Gangadharan, J. Mater. Chem., 1995, 5, 1035.
22. H. Yasushi(Nippondenso Co. Ltd.), US Pat., 5565688, Oct. 15, 1996.
23. W. Liu, G. C. Farrington, F. Chaput and B. Dunn, J. Electrochem. Soc., 1996, 143, 879.
24. L. Hernán, J. Morales, L. Sánchez and J. Santos, Solid State Ionics, 1997, 104, 205.
25. P. Fragnaud and D. M. Schleich, Sens. Actuators A, 1995, 51, 21.
26. P. Fragnaud, R. Nagarajan, D. M. Schleich and D. Vujic, J. Power Sources, 1995, 54, 362.
27. Y.-K. Sun, Solid State Ionics, 1997, 100, 115.
28. J. N. Reimers, E. W. Fuller, E. Rossen and J. R. Dahn, J. Electrochem. Soc., 1993, 140, 3396.
29. I. Kotschou, M. N. Richard, J. R. Dahn, J. B. Soupart and J. C. Rousche, J. Electrochem. Soc., 1995, 142, 2906.
30. A. R. Armstrong and P. G. Bruce, Nature, 1996, 381, 499.
31. M. M. Thackeray, J. Electrochem. Soc., 1995, 142, 2558.
32. C. Fong, J. B. Kennedy and M. M. Elcombe, Z. Kristallogr., 1994, 209, 941.
33. V. Massarotti, M. Bini and D. Capsoni, Z. Naturforsch., Teil A, 1996, 51, 267.
34. Y. Gao and J. R. Dahn, Appl. Phys. Lett., 1995, 66, 2487.
35. M. M. Thackeray, M. F. Mansuetto, D. W. Dees and D. R. Vissers, Mater. Res. Bull., 1996, 31, 133.
36. V. Massarotti, D. Capsoni, M. Bini and C. B. Azzoni, J. Solid State Chem., 1997, 128, 80.
37. R. Stoyanova, M. Gorova and E. Zhecheva, J. Phys. Chem. Solids, submitted.
38. R. Stoyanova, M. Gorova and E. Zhecheva, J. Phys. Chem. Solids, submitted.
39. C. Masquelier, M. Tabuchi, K. Ado, R. Kanno, Y. Kobayashi, Y. Maki, O. Nakamura and J. B. Goodenough, J. Solid State Chem., 1996, 123, 255.
40. K. D. Singh, S. C. Jain, T. D. Sakore and A. B. Biswas, Acta Crystallogr., Sect. B, 1975, 31, 990.
41. T. Lis, Acta Crystallogr., Sect. B, 1982, 38, 937.
42. R. Swanson, W. H. Ilsey and A. G. Stanislowski, J. Inorg. Biochem., 1983, 18, 187.
43. R. C. Bott, D. S. Sagatys, D. E. Lynch, G. Smith, C. H. L. Kennard and T. C. W. Mak, Aust. J. Chem., 1991, 44, 1495.
44. J. P. Glusker and H. L. Carrell, J. Mol. Struct., 1973, 15, 151.
45. A. Karipides and A. T. Reed, Inorg. Chem., 1976, 15, 44.
46. Y. Xia and M. Yoshio, J. Electrochem. Soc., 1997, 144, 4186.
47. S. Angelov, E. Zhecheva and D. Mehandjiev, Commun. Dep. Chem. Bulg. Acad. Sci., 1980, 13, 369.
48. C. Pirovano and S. Trasatti, J. Electroanal. Chem: Interfacial Electrochem., 1984, 180, 171.