Lithium batteries are better than Gel batteries.
Lithium batteries have higher energy density than Gel batteries as well as longer lifespans and faster charging times.
Gel batteries are more affordable and have easier maintenance but lithium batteries are still much better than Gel batteries are.
lithium batteries also have a higher percentage of stored energy than gel batteries do.
The higher energy density that lithium batteries have means the lithium battery holds more power for their size, they have a longer lifespan and can handle more charge and discharge cycles than gel batteries, and charge faster as well as have higher depth of discharge.
You can use a larger percentage of the lithium batteries capacity before needing to recharge it and they are also more efficient than gel batteries.
Lithium batteries to cost more than gel batteries and are more sensitive to temperature fluctuations and can require specialized disposal.
Some of the pros of gel based batteries are they cost less, are maintenance free, spill proof due to the gel like electrolyte and often are more resistant to vibration and temperature changes than lithium and other battery types.
However some cons of the gel batteries are they have lower energy density as well as shorter lifespan, slower charging times and lower depth discharge and less overall efficiency.
Lithium batteries are preferred where energy density, lifespan and charging speed are critical.
For applications where cost and ease of maintenance are the primary concerns then gel batteries can be a more suitable option which include for stationary backup power, certain marine applications and some industrial equipment.