Creating Sandwich-like Ti₃C₂/TiO₂/rGO as Anode Materials with High Energy and Power Density for Li-Ion Hybrid Capacitors

Li-ion hybrid capacitors (LHCs), with high energy and power density, have been becoming promising candidates for efficient energy storage. Titanium carbide (Ti 3 C 2 ) as a member of the two-dimensional transition metal carbides (MXenes) family, with fast ionic accessibility to redox reactions and remarkable electrical conductivity, showed emerging potential for developing high-performance LHCs. In this work, we reported a strategy to fabricate sandwich-like Ti 3 C 2 /TiO 2 /rGO anode materials for LHCs, during which the reduced graphene oxide (rGO) and in situ formed TiO 2 nanoparticles were created among the Ti 3 C 2 sheets. The intercalation of TiO 2 nanoparticles and rGO could prevent the restacking of Ti 3 C 2 layers and expand their interlayer space, thus increasing the active sites, shortening the ion diffusion path, and promoting the electrolyte transport. The asymmetric device, assembled by using Ti 3 C 2 /TiO 2 /rGO as the anode and LiNi 0.5 Co 0.2 Mn 0.3 O 2 as the cathode, exhibited outstanding energy density (165 W h kg –1 at 260 W kg –1 ) and power density (233 mW h cm –3 at 367 mW cm –3 ), as well as remarkable cyclic stability (83% capacity retention after 700 cycles). The synthesis of Ti 3 C 2 /TiO 2 /rGO using an in situ formation method opens a new way to develop promising anode materials for LHCs devices with excellent specific capacity and good energy and power density.