Synthesis and functionalization of 2D nanomaterials for application in lithium-based energy storage systems

The rising demands for efficient regulating the intermittency of renewable energies as well as the rapid spread of portable electronics or electric vehicles have put forward higher requirements on future energy storage systems. Based on the electrochemical reaction difference between lithium and anodes/cathodes, a series of lithium-based energy storage systems, including lithium-ion batteries, lithium-sulfur batteries, lithium-ion capacitors and lithium-oxygen batteries, have been developed and inspired increasing research enthusiasm due to their efficient energy storage features. However, from their current development status, there remains an enormous gap in energy/power density, durability and safety issues between the practical and theoretical performance. Fortunately, 2D nanomaterials, which have been widely applied in lithium-based energy storage systems due to some unique physical/chemical properties, are gradually closing the gap. Therefore, the synthesis approaches for targeting 2D nanomaterials with controlled qualities will be of great significance in this field. On the other hand, for better addressing some stubborn issues during the application, it is necessary to modify 2D nanomaterials by some effective functionalization strategies. In this review, we summarize the general synthesis approaches of 2D nanomaterials as well as functionalization strategies for high-performance lithium-based energy storage systems. Furthermore, the specific role of functionalized 2D nanomaterials in lithium energy storage will be pointed out by presenting the recent achievements in this field. A deep understanding of these works will inspire more ideas for designing 2D nanomaterials with superior performance for advanced electrochemical storage systems, including but not limited to lithium energy storage. This review summarized the general synthesis methods of 2D nanomaterials as well as functionalization strategies for high-performance lithium-based energy storage systems, including lithium-ion batteries (LIBs), lithium-sulfur batteries (LSBs), lithium-ion capacitors (LICs) and lithium-oxygen batteries (LOBs).