Will Dewalt Nano Lithium Ion Battery DC9180 replace the Ni Cad 18 volt version XRP Battery DC9096?

Probably not, or at least not for quite some time. The biggest reason COST!

Most people already know that the DC9180 battery will fit in any tool designed for the DC9096 (except the radio's, vacuums, and some flourescent flashlights depending on the date they were made.)

The DC9180 Nano battery requires the newest version battery charger (the all yellow top charger.) This new version battery charger DC9310 single charger and DC9320 dual charger) will charge all the Dewalt batteries (except the univolt batteries, univolt batteries are large cell versions made in 9.6 and 12 volt versions.)

Lithium ion Batteries are improving all the time and lots of research is going on to improve battery technology, but the DC9096 is the lowest cost 2.6Amh Dewalt XRP battery available.