You can buy little panels that clamp to the battery but they are just for trickle charging while in storage and not to actually recharge a battery. I agree with brwarrior above that your best bet is at least 100 watt panel and a controller to regulate it. Lots of posts on solar, just use the search panel above.
2017 SLX 195RB
2021 Jeep Grand Cherokee Summit L 5.7L V8
Andersen WDH hitch, Renogy 100 AH Lithium &
200 Watts solar panels from Renogy
Prev. '14 Jeep Grand Cherokee Overland, gas 3.6 V6