Nanotechnology enabled rechargeable Li-SO₂ batteries: Another approach towards post-lithium-ion battery systems

Extensive research efforts have been devoted to the development of alternative battery chemistry to replace the current technology of lithium-ion batteries (LIBs). Here, we demonstrate that the Li-SO₂ battery chemistry, already established 30 years ago, has considerable potential to be regarded as a candidate for post-LIBs when appropriate nanotechnology is exploited. The recently developed nanostructured carbon materials greatly improve the battery performances of Li-SO₂ cells, including a reversible capacity higher than 1000 mA h g^-1 with a working potential of 3 V and excellent cycle performance over 150 cycles, and provide a theoretical energy density of about 651 W h kg^-1, which is about 70% higher than that of the currently used LIBs. The nanostructured carbon cathodes offer not only an enlarged active surface area, but also a mechanical buffer to accommodate insulating discharge products upon discharge. Considering the other outstanding properties of the SO₂-based inorganic electrolyte, such as non-flammability and significantly higher ionic conductivities, wisely selected nanotechnology renders the Li-SO₂ battery chemistry a very promising approach towards the development of a post-LIB system.