it’s still a Li-ion (like most current rechargeables) but the electrolyte - the medium that transfers the ions from the anode to the cathode - (the + and -) inside the battery is made of a solid material instead of the current gen liquid ones. The benefits are less weight/size (as liquids take up more space than solids) and a more stable composition - the liquid electrolyte can’t leak - the way batteries get gunky and corroded if left for a while
And if I understand correctly, they are safer because there is less chance of parts touching inside. I don’t know the correct t terminology, but one of the big problems with current li-ion batteries is that if they get physically damaged, parts inside can touch, which basically starts a short/chain reaction that turns into a dangerous thermal runaway.
Also if I remember correctly the guy that invented li-ion invented some kind of solid state battery with glass right before he died. I’m assuming this technology stems from that.
Please correct me if I’m wrong on any of this. Knowledge is power.