Semi-solid batteries are rechargeable batteries that use semi-solid electrolytes instead of liquid or gel electrolytes in traditional lithium-ion batteries. Semi-solid electrolytes are usually composed of solid conductive materials suspended in liquid electrolytes. One of the most significant advantages over traditional liquid lithium batteries is their improved safety and stability. Semi-solid electrolytes are less prone to leakage and thermal runaway, which reduces the risk of fire or explosion.

One of the key reasons for the high energy density of semi-solid batteries is their unique electrode design. Compared with the electrodes of traditional lithium-ion batteries, the electrodes of semi-solid batteries are made of porous sponge-like materials that can absorb more active substances. This makes the battery more energy dense and has better performance. In addition, the use of semi-solid electrolytes makes the ion transport between electrodes more efficient, which further improves the energy density of the battery.