Silicon-Based Non Aqueous Anolyte for Li Redox-Flow Batteries

Although Si negative electrodes can constitute the next generation of Li-ion batteries we are still far from mastering their large volume expansion upon cycling although we have managed to limit their Li uptake to the expense of the delivered capacity. Herein we report the feasibility of achieving i) high (2800 mAh/g of Si) capacity retention, ii) stable (>98%) coulombic efficiency and low (<150 mV) polarization, with highly dispersed Si/C suspensions, hence their possible use in Li-ion Redox Flow systems. Besides, the results of such a counter intuitive approach (i.e. no Si confinement or binding) provide a new way of looking at Li-alloying systems opening new directions to design better Si-based electrodes for enhanced performances of classical or new generations Li-ion cells. (C) 2013 The Electrochemical Society. [DOI: 10.1149/2.002304jes] All rights reserved.