As you already know the primitive lead acid battery is going the way of the horse and buggy.
Energy storage in a lithium battery has advanced to the point of being very safe; very lightweight, 1/4th or less the weight of a lead battery, a longer life span; thus cheaper than SLA over time.
No battery tender required, higher resting voltage, higher cranking voltage / amps, cleaner, no gassing / no corrosion, less toxic and environmentally much greener than lead acid.
Whether you have a Lycoming or Continental or Rotax or other engines consider that a lithium replacement battery will last 5 times longer, and although costing about 2 x's more than a stock lead battery, it pays off in the long run, while providing the benefits of lighter weight and smaller size. For those infrequent flyers, a charged Aerolithium battery can sit for months and still fire up your engine.
Lithium lightweight airplane starting batteries are for those that want faster acceleration, increased useful load, shorter takeoffs and landings, have weight and balance issues, want less mass/ stress during hard G turns, no maintenance, install anywhere, and like being on the leading edge of technology.
The Lithium Iron Phosphate chemistry of these batteries are non- hazardous, non flammable and non corrosive. Extremely small self discharge , no memory like NiCd, and can be serviced / refurbished if ever. These Lithium aircraft starting batteries are a retrofit unit that will work in ANY fixed wing aircraft, helicopters, light sport planes, experimental aircraft, LSA and gyrocopters.
Engines with fuel injection or electronic ignition are highly advised to have a backup battery installed.