Li-Ion batteries use liquid electrolytes which are explosive at high temperatures, considering they are also maxed out in energy density. Hence, solid state batteries using solid electrolytes are the next-generation of batteries.
Li-Po batteries use gel polymer electrolytes or solid polymer electrolytes, which add a tiny amount of liquid electrolyte (salt-solvent mixture) to the solid matrix to enhance characteristics.
So I initially assumed that they are safer than Li-Ion. But it seems that Li-Po is more dangerous than Li-Ion. So I assumed it might be because the solid electrolyte having a higher energy density and thermal capacity means the added liquid electrolyte is also exposed to the same increased temperature and energy, making it more dangerous.
That seems to be backed up by this paper (DOI:10.1016/j.joule.2022.02.007).
Are there any other reasons for this, specifically for Li-Po batteries? I couldn't find more info regarding this provided their heavy use with drones.
One assumption I have is that Li-Po batteries lack a BMS, so their use should be carefully monitored, to prevent undercharging or overcharging in case of solar powered charging.