Surface-Modified Si Nano-Particles as New Anode Materials

Abstract

Silicon has been considered as one of the most promising anode materials for next generation high-energy lithium-ion battery due to its extremely high theoretical capacity. However, large volume expansion/contraction (~ 300%) during lithiation/delithiation process leads to rapid capacity fade during repeated cycling. The main contributor for the poor performance of Si anode is mainly due to the particle pulverization during the rapid Li+ insertion/extraction and the loss of electrical contact caused by the rearrangement of electrode structure. Nano Si material has shown positive impact on the cell performance. Compared with bulk Si, nanostructured Si (<150 nm) largely resolved the pulverization issue. However, the intrinsic electrolyte reactivity with the lithiated Si particles still exists resulting in the gradual active lithium loss and capacity degradation. In this presentation, a novel approach attempting to stabilize the surface of the Si particles is reported. Plasma synthesized silicon nanocrystals with Si-H terminal groups were subject to hydrosilylation with various organic compounds containing an allyl group as shown in Figure 1. Preliminary results indicate that the surface functionalization could stabilize the Si/electrolyte interface affording much improved Coulombic efficiency and cycling performance. The latest progress will be presented. Figure 1