Demonstrating the Feasibility of Al as Anode Current Collector in Li-Ion Batteries via In Situ Neutron Depth Profiling

The viability of using aluminum (Al) foil as the anode current collector in Li-ion batteries was demonstrated using in situ neutron depth profiling (NDP). A 500 nm thin Sn film, physical vapor deposited onto an Al foil, was monitored using NDP during lithiation and subsequent delithiation. Results indicate exclusive lithiation of the Sn electrode throughout the 0.05 to 1.00 V vs Li/Li+ range, leaving the Al foil current collector unlithiated even at the low potentials sufficient to lithiate Al. Additionally, 60-80 nm Sn nanoparticles suspended in a polyvinylidine fluoride (PVDF) matrix were cast onto an Al foil current collector and lithiated under constant current (C/6 rate). Results indicate the preferential lithiation of Sn nanoparticles. At lithiation potentials >0.3 V, Al lithiation is avoided even when the current collector is in direct contact with the electrolyte solution.