Graphene-coupled Ti₃C₂MXenes-derived TiO₂mesostructure: promising sodium-ion capacitor anode with fast ion storage and long-term cycling

Abstract

Graphene coupled Ti3C2MXenes-derived TiO2mesostructure with robust Na-ion charge storage properties enables the fabrication of high-performance Na-ion capacitors.

Mesopore‐Induced Ultrafast Na+‐Storage in T‐Nb2O5/Carbon Nanofiber Films toward Flexible High‐Power Na‐Ion Capacitors

“…For example, flexible SCs based on graphene frameworks, carbon nanotube architectures, carbon nanofiber membranes, and pyrolyzed bacterial cellulose, exhibit an ultrahigh power density of over 50 kW kg −1 and an outstanding cycling durability (>10 000 cycles), while the energy density of these SCs is low (usually <10 Wh kg −1 ) due to the limited charge accumulation. In contrast to SCs, flexible LIBs show a high energy density (150–300 Wh kg −1 ) but usually possess low power density and poor cycle life (<1000 cycles) because of the sluggish solid‐state ion diffusion in electrodes . Therefore, many works are focused on the development of hybrid lithium (or sodium)‐ion capacitors (LICs and NICs), which could combine the complementary advantages of a battery‐type anode and a capacitive cathode from the different work mechanisms in one device.…”

Hierarchical Porous Activated Carbon Obtained by a Novel Heating‐Rate‐Induced Method for Lithium‐Ion Capacitor

“…With a looming depletion of traditional energy sources and deteriorating environment, the increasing application for high performance electronic equipment has motivated researchers to develop an advance energy storage system to storage intermittent renewable energy and guarantee the availability of on‐demand energy and power . Supercapacitors (SCs) and secondary batteries are two major devices for electric energy storage and have gained significant attention in the past decades .…”

Flexible Na batteries

“…A flexible anode of TiO 2 nanorods grown on carbon cloth was synthesized by a hydrothermal method and subsequent heat treatment. 60,62 Macroporous 3D Ti 3 C 2 T x films were prepared via a sacrificial template method using 2D Ti 3 C 2 T x MXene flakes self-assembled onto polymer surfaces. Na 2 Ti 3 O 7 , with an open-layered framework in zigzag layers, showed a high theoretical capacity and a low voltage plateau at~0.3 V vs Na/Na + .…”

“…However, its low electrical conductivity and structural instability limit its practical application. 60,61 An anode composed of Na 2 Ti 3 O 7 nanowires with lengths of >100 mm and a width of 100-200 nm was grown on a carbon cloth substrate via a hydrothermal method, as shown in Figure 3B. 52 As a binderfree flexible anode, this composite electrode demonstrated excellent cyclability with a capacity retention of over 96% after F I G U R E 3 Flexible anodes for flexible Na batteries.…”

“…Ti-based transition metal carbides (Mxenes) have also attracted intense attention in NIB anodes due to their layered structure, which is suitable for Na + intercalation. 60,62 Macroporous 3D Ti 3 C 2 T x films were prepared via a sacrificial template method using 2D Ti 3 C 2 T x MXene flakes self-assembled onto polymer surfaces. 63 The obtained free-standing and flexible films could be directly used as anodes for NIBs, in which reversible capacity of~330 mAh g −1 was obtained at a rate of 0.25C and a reversible capacity of 295 mAh g −1 was retained at 2.5C after 1000 cycles.…”