Silicon and tin are interesting candidates for anode materials in Lithium ion batteries as they have some of the highest theoretical specific capacities (4200 mAh g^-1 for silicon and 991 mAh g^-1for tin).[1] This advantage is counteracted by a major volume expansion with subsequent contraction during lithiation and delithiation. This expansion is causing the electrode to pulverize, lose electrical contact and thus leading to a quick fade in capacity. Pulverization may be avoided when nanoparticles or nano-sized polymers are used as they are small enough to allow “active material breathing” and thus to evade a breakdown of the electrode.[2]

Organosilicon and organotin hydrides have been studied as precursors in the formation of nano-sized polymeric materials which consist of a backbone of covalently bonded metal atoms.[3] These materials feature an increased degree of electron delocalization and may therefore be interesting for the use in charge-transfer devices and Li-ion batteries.[4] We focused on the synthesis, characterization and possible application of differently substituted arylsilicon and aryltin hydrides and their respective nanoparticles and nano-sized polymers.[5]

Moreover we synthesized aryl-substituted silicon and tin hydrides of the types R₃EH, R₂EH₂ and REH₃ (R = phenyl, 1-naphthyl; E = Si, Sn) as precursor materials and characterized them using cyclic voltammetry. The precursors were then pyrolysed or polymerized, respectively, and the resulting nanoparticles were incorporated within anodes of Li-ion batteries.

Herein we report first electrochemical characterization of differently aryl-substituted silicon and tin hydrides using cyclic voltammetry methods. Additionally, these precursor materials as well as their respective nanoparticles were tested as anode materials in Li-ion half-cells.

References:

[1] a) C.K. Chan et al., Nat. Nanotechnol., 2008, 3, 31-35. b) B. Veeraraghavan, A. et al., J. Electrochem. Soc., 2002, 6, A675-A681.
[2] X. Xiao et al., Adv. Funct. Mater., 2015, 25, 1426-1433.
[3] a) F. Choffat, P. Smith, W. Caseri, J. Mater. Chem., 2005, 15, 1789-1792. b) K. Schittelkopf, R.C. Fischer, S. Meyer, P. Wilfling, F. Uhlig, Appl. Organomet. Chem., 2010, 24, 897-901.
[4] a) S. Adams, M. Dräger, Main Group Met. Chem., 1988, 11(3), 151-180. b) F. Choffat, P. Smith, W. Caseri, Adv. Mater, 2008, 20, 2225-2229.
[5] a) C. Zeppek, Dissertation, 2015, University of Technology Graz. b) C. Zeppek, et al., J. Organomet. Chem., 2013, 740, 41-49. c) C. Zeppek, et al. in preparation.