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

Abstract

Li-ion hybrid capacitors (LHCs), with high energy and power density, have been becoming promising candidates for efficient energy storage. Titanium carbide (Ti3C2) 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 Ti3C2/TiO2/rGO anode materials for LHCs, during which the reduced graphene oxide (rGO) and in situ formed TiO2 nanoparticles were created among the Ti3C2 sheets. The intercalation of TiO2 nanoparticles and rGO could prevent the restacking of Ti3C2 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 Ti3C2/TiO2/rGO as the anode and LiNi0.5Co0.2Mn0.3O2 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 Ti3C2/TiO2/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.