In the last 50 years the biggest advances come from Hydrogen integration in to our lives. It's now being used inside homes with hydrogen appliances (UK), hydrogen cars slowly being tried but due to explosiveness of hydrogen still going slow, renewable wind and solar plants beginning to use hydrogen as a storage with many studies going on right now across the world.
Use your rockets fuel tank for storage of hydrogen. Probably Dynatics or National Team are the ones which would work best for this, but StarShip is ideal for large cargo transports. They will be permanently kept on the Moon as a mobile storage medium. They will also serve as lifeboats in case of emergency. Convert electricity to hydrogen and back as needed. Additional benefit is portability this would allow, because you can fly the rocket to any new location and have power reserves instantly available there.
In space temperatures are close to absolute zero. Use superconductive circuit to pump voltage to a maximum. Later distribute it as needed similarly to water tower.