Li-ion batteries with silicon anodes: study of innovative electrolytes based on carbonates

An innovative electrolyte for promising Si-based anode materials for Li-ion and post-Li-ion batteries is studied. Silicon features a tenfold theoretical specific capacity compared to graphite, although it presents the intrinsic disadvantages of a severe volume expansion during lithiation (about 300%), that undermines the lifetime of the device. The combination of a newly formulated electrolyte with an active material consisting of silicon nanoparticles incorporated into β-cyclodextrins-based nanosponges matrix and reduced graphene oxide permits to overcome Si-related issues. Starting from a mixture of ethers typical of Li-S cells, devised to obtain an electrolyte suitable for a future high energy and high capacity Si-S cell, FEC 5 wt% is used and electrochemical tests show markedly improved performance with respect to VC-based standard electrolytes. XRD, EIS and CV studies highlight an increased activation of silicon and a less resistive SEI layer. Overall, a favorable interaction of the newly formulated electrolyte with the nanosponges-based matrix leads to more durable and efficient cells.