Mechanical energy storage, like pumped hydro or flywheel. Thermal energy storage, like molten salt.
Electrochemical isn’t entirely off the table either: less-volatile chemistries are available, and better containment methods can reduce risks.
Non-electrical chemical storage methods are available: electrical energy can be used for hydrogen electrolysis, or Fischer-Tropsch hydrocarbon fuels. Fuel cells, traditional ICE generators, or export it from the electrical generation industry to the transportation industry.
There’s also avoiding (or minimizing) the need for storage at all, with “demand shaping”. Basically, we radically overbuild solar, wind, wave, tidal, etc. Normally, that would tank energy prices and be unprofitable, but we also build out some massive, flexible demand to buy this excess power. Because they are extremely overbuilt, the minimal output from these sources during suboptimal conditions is more than enough to meet normal demands; we just shut off the flexible additional demand we added.
Petrol fires use oxygen from the air. They can be extinguished by removing the oxygen: covering it in firefighting foam, or displacing it with CO2, for example.
Batteries contain both their fuel and their oxidizer together in one case. You can’t remove the oxygen. So long as they are hot enough, they keep burning, even if they are underwater. The only way to extinguish them is to remove the heat. Which is practically impossible.