Achieving of Flexible, Free‐Standing, Ultracompact Delaminated Titanium Carbide Films for High Volumetric Performance and Heat‐Resistant Symmetric Supercapacitors

Advanced Energy Materials

Liang

et al. 2019

212

156

The fabrication of fully printable, flexible micro‐supercapacitors (MSCs) with high energy and power density remains a significant technological hurdle. To overcome this grand challenge, the 2D material MXene has garnered significant attention for its application, among others, as a printable electrode material for high performing electrochemical energy storage devices. Herein, a facile and in situ process is proposed to homogeneously anchor hydrous ruthenium oxide (RuO2) nanoparticles on Ti3C2Tx MXene nanosheets. The resulting RuO2@MXene nanosheets can associate with silver nanowires (AgNWs) to serve as a printable electrode with micrometer‐scale resolution for high performing, fully printed MSCs. In this printed nanocomposite electrode, the RuO2 nanoparticles contribute high pseudocapacitance while preventing the MXene nanosheets from restacking, ensuring an effective ion highway for electrolyte ions. The AgNWs coordinate with the RuO2@MXene to guarantee the rheological property of the electrode ink, and provide a highly conductive network architecture for rapid charge transport. As a result, MSCs printed from the nanocomposite inks demonstrate volumetric capacitances of 864.2 F cm−3 at 1 mV s−1, long‐term cycling performance (90% retention after 10 000 cycles), good rate capability (304.0 F cm−3 at 2000 mV s−1), outstanding flexibility, remarkable energy (13.5 mWh cm−3) and power density (48.5 W cm−3).

Section: Resultsmentioning

confidence: 99%

Hydrous RuO₂‐Decorated MXene Coordinating with Silver Nanowire Inks Enabling Fully Printed Micro‐Supercapacitors with Extraordinary Volumetric Performance

Advanced Energy Materials

Liang

et al. 2019

212

156

“…The electrochemical kinetics can be evaluated by the b-value. [29][30][31] = + q q q [28,29] The b-values can be obtained from the slope of particular potentials log(i)-log(v) plot and the results are shown in Figure 5b.…”

Section: Wwwadvelectronicmatdementioning

confidence: 99%

“…[29][30][31] Therefore, the total charge measured by cyclic voltammetry (q (v) ) can be calculated by the following equation.…”

Section: Wwwadvelectronicmatdementioning

confidence: 99%

“…[34] In addition, there is a subvertical line at low frequency region, indicating great electrochemical capacitive behavior of the AFSC. [31,35] The maximum volumetric specific capacitance of the entire device (C V ) is 2.86 F cm −3 . With the current density increases, the value of C V gradually decreases to 2.05 F cm −3 as shown in Figure 6d.…”

Section: Wwwadvelectronicmatdementioning

confidence: 99%

See 1 more Smart Citation

Compressible All‐In‐One Supercapacitor with Adjustable Output Voltage Based on Polypyrrole‐Coated Melamine Foam

Zang

Qiao

et al. 2019

Adv Elect Materials

electrochemical properties, and light weight has attracted widespread attention from academic and industrial fields. [1][2][3][4][5][6][7][8] Among numerous flexible energy storage devices, flexible supercapacitors are often regarded as the optimal candidate on account of their high power density, ultralong cycling stability, and fast charge and discharge capacity. [9][10][11][12] Recently, substantial effort has been devoted to endow flexible supercapacitors with more efficiency, more stability, and low cost in order to develop fully flexible electronics. [13][14][15] High energy density and good mechanical durability are the major difficulties in design and fabrication of flexible supercapacitors. Generally, the common flexible supercapacitors exhibit a multilayer laminated configuration, which are fabricated by placing a gel electrolyte layer between two flexible electrodes. [16][17][18][19] Compared with the common flexible supercapacitors with laminated structure, the major components of the all-inone flexible supercapacitors including two electrodes, separator, electrolyte, and current collectors are integrated on the same substrate. [20,21] This integrated design cannot noly reduce the contact resistance of the interface but also increase the mechanical durability including compression stability and stretching and/or twisting reliability.To date, a series of integrated flexible supercapacitors have been reported. Guo et al. reported healable supercapacitors with all-in-one configuration by in situ polymerization and deposition of single-walled carbon nanotube (SWCNT) and polyaniline (PANI) onto the two sides of the healable hydrogel electrolyte separator. [17] Wang et al. integrated the electrode-electrolyte-electrode component in a free-standing poly(vinyl alcohol) chemical hydrogel film to fabricate an all-in-one supercapacitor. [22] Gao et al. designed an all-in-one asymmetric supercapacitor with high volumetric energy density by electrodeposition of metallic oxide onto each side of the carbon nanotube (CNT) modified porous polyamide nanofiber film. [23] Shao et al. fabricated a tunable integrated flexible supercapacitor using three dimensional reduced graphene oxide/graphene oxide/reduced graphene oxide (3D rGO/GO/rGO) foam via the laser direct writing technology. [24] These all-in-one supercapacitors can avoid unstable physical connection, which is of great important for Compared with laminated structure supercapacitors, all-in-one supercapacitors can reduce the contact resistance of the interface and avoid displacement/delamination of the multilayer structure under deformation, which suggests a highly promising energy-storage device. However, simplifying the assembly process to achieve high voltage output, balance mechanical stability and electrochemical performance is still a serious challenge. Here, an all-inone flexible supercapacitor (AFSC) is designed based on melamine foam and polypyrrole by one-step polymerization method. It exhibits a high volumetric specific capacitance of 2.86 F cm −3 , vol...

“…[30][31][32] The MXenes have already showed their significant applicability in biosensors, [33] electromagnetic wave absorption, [34] supercapacitors, [35,36] Li-ion batteries, [37,38] electronic devices, [39,40] gas sensors, [41] etc., because of their high conductivity, [42] hydrophilic surface, [43] and flexibility. Their general formula is recorded as M n+1 X n T x , where "M" stands for the transition metal element, "X" is C or N or CN, while T x represents the terminal groups of -OH or -F, etc., and n could be 1, 2, or 3.…”

mentioning

confidence: 99%

High‐Performance Electrocatalytic Conversion of N₂ to NH₃ Using Oxygen‐Vacancy‐Rich TiO₂ In Situ Grown on Ti₃C₂T_x MXene

Fang

Advanced Energy Materials

Han

et al. 2019

367

To achieve the energy‐effective ammonia (NH3) production via the ambient‐condition electrochemical N2 reduction reaction (NRR), it is vital to ingeniously design an efficient electrocatalyst assembling the features of abundant surface deficiency, good dispersibility, high conductivity, and large surface specific area (SSA) via a simple way. Inspired by the fact that the MXene contains thermodynamically metastable marginal transition metal atoms, the oxygen‐vacancy‐rich TiO2 nanoparticles (NPs) in situ grown on the Ti3C2Tx nanosheets (TiO2/Ti3C2Tx) are prepared via a one‐step ethanol‐thermal treatment of the Ti3C2Tx MXene. The oxygen vacancies act as the main active sites for the NH3 synthesis. The highly conductive interior untreated Ti3C2Tx nanosheets could not only facilitate the electron transport but also avoid the self‐aggregation of the TiO2 NPs. Meanwhile, the TiO2 NPs generation could enhance the SSA of the Ti3C2Tx in return. Accordingly, the as‐prepared electrocatalyst exhibits an NH3 yield of 32.17 µg h−1 mg−1cat. at −0.55 V versus reversible hydrogen electrode (RHE) and a remarkable Faradaic efficiency of 16.07% at −0.45 V versus RHE in 0.1 m HCl, placing it as one of the most promising NRR electrocatalysts. Moreover, the density functional theory calculations confirm the lowest NRR energy barrier (0.40 eV) of TiO2 (101)/Ti3C2Tx compared with Ti3C2Tx or TiO2 (101) alone.