Mesoporous Silicon Nanostructures by Pulsed Laser Deposition as Li-ion Battery Anodes

Silicon is very attractive as active material for Li-ion battery anodes due to its high theoretical capacity, but proper nanostructuring is needed to accommodate the large volume expansion/shrinkage upon reversible cycling. This would overcome the destructuration induced by the lithiation/delithiation processes, often resulting in poor long-term performance. Hereby, novel mesoporous silicon nanostructures are grown at room temperature by Pulsed Laser Deposition (PLD) directly on top of the Cu current collector surface, and their promising electrochemical behaviour demonstrated in lab-scale lithium cells. Depending on the porosity, easily tunable by PLD, initial specific capacities approaching 300 Ah/cm2 are obtained with a quasi-stable reversible cycling. Engineering voids at the nanoscale, by direct introduction of specific porosity during growth, opens up the route for the effective use of silicon as lithium battery anode without the need for any binder or conductive additive which would lower the overall energy density.