A MXene‐Coated Activated Carbon Cloth for Flexible Solid‐State Supercapacitor

Abstract

Herein, a new electrode material HHK‐CC@Ti3C2TX (HHK‐CC = activated carbon cloth, TX = F, O, or OH) for a flexible solid‐state supercapacitor (SSC) is prepared by a simple method. The activated carbon cloth (HHK‐CC) is obtained by treating with potassium permanganate beforehand. The specific area, oxygen‐containing functional group, hydrophilicity, and electrical conductivity of the activated CC are increased significantly after the potassium permanganate treatment. A few layers of Ti3C2TX flakes are coated directly on the HHK‐CC. When the loading Ti3C2TX on the HHK‐CC@Ti3C2TX electrode is 3 mg cm−2, the prepared electrode achieves a high capacitance of 1033 mF cm−2 at the current density of 1 mA cm−2. After assembling as a symmetrical SSC, the flexibility and mechanical strength of the CC are still preserved and no significant capacitance decreasing is observed under the conditions of bending and deformation. The capacitance value remains at 94.2% after 1000 cycles, and a high power density of 0.779 W cm−2 is obtained at the energy density of 4.5 μWh cm−2. This work gives a new strategy for designing flexible supercapacitors.

MXene/N-Doped Carbon Foam with Three-Dimensional Hollow Neuron-like Architecture for Freestanding, Highly Compressible All Solid-State Supercapacitors

“…When the current density increases to 30 A g –1 , the specific capacitance can still be retained at 331 mF cm –3 (40 F g –1 ). This value of the MXene/NCF-based SSC device is comparable to the other MXene-based supercapacitors devices, such as graphene-wrapped MXene (54 mF cm –2 ), MXene-coated activated carbon cloth (413 mF cm –2 ), and titanium carbide (309 mF cm –2 ). − …”

“…The Ragone diagram is shown in Figure e. The maximum energy density of the MXene/NCF-based SSC device can be up to 8.75 Wh kg –1 (0.072 mWh cm –3 ), and the maximum power density is 1871 W kg –1 (15.5 mW cm –3 ), which is higher than some recently reported SSC devices, such as NCF-based elastic symmetric supercapacitors (0.018 mWh cm –3 ), Ti 3 C 2 T x -based flexible symmetric supercapacitors (315 mWh kg –1 ), TiO 2 @PPy-based flexible symmetric supercapacitors (0.013 mWh cm –3 ), MnO 2 /Ti 3 C 2 -based flexible symmetric supercapacitors (8.3 Wh kg –1 ), NPCA-based symmetric supercapacitors (6.8 Wh kg –1 ), SUMBC-based flexible supercapacitors (5.41 Wh kg –1 ), commercial activated carbon-based flexible supercapacitors (8.3 Wh kg –1 ), and PCNPs-semi-solid-state supercapacitors (7.9 Wh kg –1 ). ,,− …”

Continuous Fabrication of Ti3C2Tx MXene-Based Braided Coaxial Zinc-Ion Hybrid Supercapacitors with Improved Performance

“…3 e, the Nyquist curve obtained in frequencies ranging from 100 kHz to 0.01 Hz confirmed the low charge transport resistance of 4.41 Ω. Figure 3 f displays the compared energy and power densities of this FSC device and reported works; the highest energy density of 42.8 μWh cm − 2 at a power density of 0.64 mW cm − 2 of our devices can be calculated, which is much higher than that of recently reported works as shown in Table 1 [ 31 – 40 ]. Figure 3 g exhibits the capacity retention of the braided coaxial FSC after 5000 charge/discharge cycles at a current density of 20 mA cm − 2 ; 83.6% of initial value was remained with high Coulombic efficiency of about 100%, suggesting the outstanding cycling stabilities of the fabricated Zn//Ti 3 C 2 T x FSC.…”

Advanced Tri-Layer Carbon Matrices with π–π Stacking Interaction for Binder-Free Lithium-Ion Storage

“…Due to their increasing demand in sustainable and renewable energy sources, lithium-ion batteries (LIBs) remain one of the most energy-harvesting materials in the past 3 decades. , As electrode materials continue to be the center of current research worldwide, − converting commercial carbon cloth (CC) to functionalized CC has attracted significant attention as the strategy to achieve a promising electrode material for SCs. − For example, through different methods, , such as chemical − and electrochemical activation methods, ,, CC, which has a relatively low capacitance, has been reported to exhibit enhanced SC performance, − even better than that of certain other pseudocapacitance-based electrodes. ,, The enhanced storage ability is usually attributed to the oxygen-containing functional groups. − However, CC synthesized by such activation processes comparatively shows no storage performance as anode material for LIBs, thus limiting the use of CC directly as an LIB anode. Moreover, from the aspect of advanced functional materials, tuning the intrinsic and surface properties of CC to achieve distinct and rare features holds great relevance but is hugely challenging.…”