Engineering of electrolyte ion channels in MXene/holey graphene electrodes for superior supercapacitive performances

Fabrication of porous Ti3C2Tx MXene films by in situ foaming strategy for unparalleled high-rate energy storage

“…Different efforts, for instance, template methods and foaming methods, have been put forward to address this problem and significant progress has been made. [10][11][12][13] However, certain template methods relying on post-annealing to remove templates, such as polymethyl methacrylate microspheres, 10 polystyrene microspheres, 14 or sulfur particles, 15 and some foaming methods depending on sudden heating to induce the removal of functional groups and generation of gas molecules, 16 may simultaneously lead to the loss of long-range order of the film and oxidation of MXenes. Moreover, for subsequent electrochemical reactions, the elimination of surface hydrophilic groups and water intercalated between MXenes during annealing will result in poor electrolyte wettability and inferior ion transport between MXene layers since protons in acid electrolyte could possibly transport via the Grotthuss mechanism with the help of confined water.…”

Graphene Film with a Controllable Microstructure for Efficient Electrochemical Energy Storage

“…Among various electrode materials, graphene, owing to its high theoretical specific surface area (SSA, 2630 m 2 g –1 ), outstanding electrical conductivity (∼10 7 S m –1 ), excellent mechanical strength, high compatibility, and flexibility, is recognized as one of the ideal electrode materials for ESDs. − However, the π–π stacking force between graphene sheets attracts the adjacent sheets together and further leads to a serious decrease of the SSA. − This phenomenon will inevitably result in a lower amount of accessible active sites for ion adsorption and sluggish ion transportation speed during charging, which is unfavorable to obtain ESDs with high electrochemical performance. To alleviate the aggregation of graphene sheets, different strategies are applied, such as using nanomaterials as a spacer between graphene sheets, preparing graphene hydrogel or aerogel, etc. − Using these methods, most of the modified graphene-based electrodes exhibit higher SSA and better electrochemical performance.…”

Few-layered Ti3C2TXcoupled with Fe3O4nanoparticles assembled in a reduced graphene oxide hydrogel as advanced electrodes for high-energy supercapacitors

“…[28][29][30][31] To avoid self-stacking, one viable solution is to integrate the Fe 3 O 4 @Ti 3 C 2 T X heterostructures into a 3D interlinked framework which can not only impede self-restacking, but also produce abundant active sites and facile ion/electron transfer pathways to boost the electrochemical reaction kinetics. 25,32,33 In order to construct 3D porous architecture, the sol-gel method is more facile and low cost, compared to other methods. Moreover, the sol-gel strategy would not introduce some electrochemical inert additive (e.g., binder), and thereby the reduction of energy density is avoided.…”

“…28–31 To avoid self-stacking, one viable solution is to integrate the Fe 3 O 4 @Ti 3 C 2 T X heterostructures into a 3D interlinked framework which can not only impede self-restacking, but also produce abundant active sites and facile ion/electron transfer pathways to boost the electrochemical reaction kinetics. 25,32,33…”