Designing double-layered Si and Si/LATP nanocomposite anode for high-voltage aqueous lithium-ion batteries

Abstract

A novel anode design is demonstrated with Si nanostructures with double-layered protection for an aqueous rechargeable Li-ion Battery (ARLIB). Si nanoparticle-embedded LATP (lithium aluminum titanium phosphate; Li1.3Al0.3Ti1.7(PO4)3), as well as LATP-PVDF polymer nanocomposites, is used as the protective layers. The unique anode structure is expected to be useful in overcoming the cathodic challenges and subsequent gas evolution reactions, thus widening the operating voltage of an ARLIB up to 3.5 V. The layered anodes exhibited discharge capacities of 2630 mAh g−1 at 0.1 C as half cells in 2 M Li2SO4 aqueous solution as the electrolyte. They are also coupled with LiFePO4 cathode, and the full cells demonstrate a discharge capacity of 123 mAh g−1 with the calculated energy density values of 138 Wh kg−1 which is comparable with the conventional organic electrolyte-based LIBs. They can cycle 500 times with capacity retention of more than 75%. Hence, the conclusions from the present study project a promising anode design for ARLIBs, with high capacities and long cycling stabilities.