Scalable 3D Self‐Assembly of MXene Films for Flexible Sandwich and Microsized Supercapacitors

Abstract

The self‐assembly of large‐area MXene films is the main step to realize their applications in various energy storage devices. However, the scalable self‐assembly of flexible thin MXene films with high conductivity as well as excellent mechanical and electrochemical properties is still a challenge. Herein, a synchronous reduction and self‐assembly strategy to fabricate flexible MXene films is developed, where MXene films are synchronously reduced and self‐assembled on the Zn foil surface. Furthermore, the self‐assembly of MXene films can be scaled up by controlling the area of Zn substrates. By adjusting the patterns of Zn substrates, the interdigital MXene patterns can also be obtained via a selectively reducing/assembling process. The resultant MXene films demonstrate high electrical conductivity, large specific surface area, and excellent mechanical properties. Thus they can serve as the electrodes of flexible supercapacitor devices directly. As a proof of concept, flexible sandwich and microsized supercapacitors are designed based on the above MXene film electrodes. Both sandwich and microsized supercapacitors display stable electrochemical performance under various bending states. This study provides a route to achieve large‐area MXene‐based films or microsized structures for applications in the field of energy storage.

Micro‐Redoxcapacitor: A Hybrid Architecture Out of the Notorious Energy‐Power Density Dilemma

“…[ 19,20 ] This results in limited charge storage capacity and sluggish charge transfer kinetics, thus low areal capacitance and rate performance. [ 21–25 ]…”

“…[19,20] This results in limited charge storage capacity and sluggish charge transfer kinetics, thus low areal capacitance and rate performance. [21][22][23][24][25] It is well-known that inorganic/organic nanopillars can be inserted between MXene nanosheets to mitigate the restacking of MXenes nanosheets and expand the interlayer space. [26][27][28][29][30] Nevertheless, the extent of capacity and rate improvements is limited as conventional nanospacers exhibit neither high charge storage capacity nor electrochemical activity.…”

Hierarchical Cobalt‐Nickel Double Hydroxide Arrays Assembled on Naturally Sedimented Ti3C2Tx for High‐Performance Flexible Supercapacitors

“…The O 1s spectrum can be fitted with four subpeaks at 529.6, 530.9, 531.8, and 533.3 eV assigned to OTi, CTiO x , CTi (OH) x , and H 2 O (Figure 2g). [36,37] In the Co 2p spectrum of CoNi-DH@ Ti 3 C 2 T x in Figure 2h, the peaks at 797.0/781.5 and 795.1/779.9 eV stem from Co 2+ and Co 3+ , indicating that the hierarchical nanoarrays contain both Co 2+ and Co 3+ . There are two shakeup satellite peaks at 802.6 and 786.6 eV (indicated as "'Sat.").…”

Prospective advances in MXene inks: screen printable sediments for flexible micro-supercapacitor applications

“…In pursuit of alternative efficient methodologies, screen-printing, 90 spin coating, 91 and spray coating 92 of 2MXene as electrode patterns have found effective in the production of large-scale flexible thin-film MSCs. However, the thickness of patterns produced and the wastage of materials are considerably high and uncontrollable in the case of spin and spray coating methodologies.…”