design for portable pv charging for 97Wh lithium ion battery
You have at least two options. The power from the panel can go 1) through a "charger" that produces 24V DC @ 2A, or 2) through an "inverter" that produces 120V AC @ 2A.
The advantage of option 2) is that you can plug your device just like you normally do (wall plug), but is less power efficient.
The advantage of option 1) is that it is more power efficient, but you have to "pull out" the battery and connect it to the charger.
The equipment for either method is readily available on eBay (less than $100).
Your 100W panel should be able to charge your battery in 2 to 3 hours.

Just remember that Li batteries can burst into flames.  Make sure the charger is current and voltage limited!