Controlled High‐Capacity Storage of Lithium‐Ions Using Void‐Incorporated 3D MXene Architectures

Abstract

MXene, an example of 2D transition metal carbides, has recently been explored as an energy storage material for batteries or supercapacitors due to its high electrical conductivity and tunability of functional moieties. As with other 2D nano‐materials, however, attempts to harness MXene‐based electrodes have been limited by deterioration in mass transfer owing to self‐stacking and aggregation problems of MXenes. Here, means of creating 3D‐structured MXene films having voids of controlled size using templated co‐assembly between MXene nanosheets and monodisperse colloidal particles are presented. Using a 3D‐structured MXene‐only film incorporating microscale voids as a thin‐film electrode for Li‐ion batteries yield an initial specific capacity of 435.4 mAh g−1 at a current density of 0.01 A g−1 and highly extended cyclic stability persisting 1200 cycles, approaching the reported theoretical capacity of MXene even without employing any binder or conductive species. Electrochemical analyses reveal that the improved specific capacity is attributable to enhanced contribution of pseudo‐capacitive Li‐storage compared to diffusion‐mediated capacity, as incorporated voids tend to facilitate ionic transport into the interior region of the MXene films. Therefore, this work offers a concrete understanding to realize improved electrochemical performances of 2D nanomaterial‐based electrodes, especially in the form of free‐standing thin films.

Research and Application Progress of Conductive Films in Energy Storage Devices

“…At 1C, the activated electrode achieves a stable capacity of 1200 mA h g −1 over 100 cycles, and the coulombic efficiency is close to 100%. Min et al [143] prepared 3D MXene films with controllable size voids by templated co-assembly between MXene nanosheets and monodisperse colloidal poly(methyl methacrylate) (PMMA) particles, its cross-section field emission scanning electron microscope image is shown in Figure 12g. According to the inherent spherical shape of PMMA particles, the sintered and void-containing MXene films exhibit a favorable globular shape, which confirms the effectiveness of the template synthesis of 3D MXene films.…”

“…g) Cross-sectional field emission scanning electron microscopy images of MXene films with 8.0 μm-sized PMMA; h) Cyclic charge-discharge profiles of 8μm-Ti 3 C 2 sample; i) Long-term cyclic performance of 8 μm Ti 3 C 2 at 500 mA g −1 . Adapted with permission [143]. Copyright 2016, Wiley-VCH GmbH.…”

MXenes as Li-Ion Battery Electrodes: Progress and Outlook

“…Min et al . investigated the structural impact of incorporation of 3D voids of controlled size on the electrochemical mechanism of MXene films when used as an anode for the Li-ion batteries.…”

Simultaneously intensified plasmonic and charge transfer effects in surface enhanced Raman scattering sensors using an MXene-blanketed Au nanoparticle assembly

“…The synthesis of MXene 2D nanosheets was performed by the minimally intensive layer delamination (MILD) method as presented in our previous work. 25 In brief, 12.5 mL of hydrochloric acid (HCl, Samchun Chemical) at a concentration of 6 M and 0.8 g of lithium uoride powder (LiF, Alfa Aesar) were mixed to produce hydrogen uoride (HF) solution. Then, 1 g of titanium aluminum carbide powder (Ti 3 AlC 2 , American Elements, >98 wt%, 200 mesh) was slowly added into the produced HF solution.…”