Manipulating the Interlayer Spacing of 3D MXenes with Improved Stability and Zinc‐Ion Storage Capability

Abstract

2D transition metal carbides/nitrides (MXenes) have excellent physicalchemical properties, which makes them promising for electrochemical energy storage devices. However, because of their inherent self-stacking and narrow interlayer spacing, it is rarely used in multivalent ion energy storage systems. In this study, fatty diamines and aromatic diamines with different molecular sizes are inserted between MXene interlayers as pillars through a one-step amination process to inhibit the self-stacking and obtain different expanded interlayer spacings with improved antioxidant stability. X-ray diffraction results show that interlayer spacing of MXene increases from 1.23 to 1.40 nm. The p-phenylenediamine-intercalated MXene (PDA-MXene) exhibits better matching interlayer spacing (1.38 nm) and pore structure for improved electrolyte-accessible surface area, enhanced charge-transport properties, and promoted Zn 2+ ions storage. Therefore, zinc-ion hybrid supercapacitor (ZHSC) using PDA-MXene as cathode exhibits higher specific capacitance (124.4 F g −1 at 0.2 A g −1 ) in 2 m ZnSO 4 electrolyte together with outstanding cycling stability (85% capacity retention after 10 000 cycles at 1 A g −1 ). This study provides a route for precise control of MXene interlayer spacing by small organic molecules, which can be used to observe efficient charge storage in MXene-based electrochemical energy storage devices by optimizing interlayer spacing.

Tailoring Conductive 3D Porous Hard Carbon for Supercapacitors

“…The narrow d ‐spacing and low specific surface area lead to low active sites and hinder ion transport, which would limit electrochemical performance. [ 26 ] Raman spectra also reflect the structural difference among various hard carbon samples (Figure 3c). The D band at ≈1340 cm −1 is commonly ascribed to the defects and edges of graphitic carbon materials, and the intensity ratio of D band to G band (≈1570 cm −1 ) suggests the defective degree of carbon materials.…”

The Emergence of 2D MXenes Based Zn‐Ion Batteries: Recent Development and Prospects

“…[ 184 ] Peng et al. [ 176 ] have selected four diamine molecules of different sizes, ethylenediamine, 1,3‐propanedinamine, 1,4‐butanediamine and p‐phenylenediamine as pillars to adjust the interlayer spacing of MXene. Such pillars also act as a cross‐linking representative to homogeneously cross‐link MXene to make hydrogels (denoted as EDA‐MXene, PrDA‐MXene, BDA‐MXene, and PDA‐MXene, respectively).…”

“…h,i) Reproduced with permission. [176] Copyright 2021, American Chemical Society. and decrease local current density in plating/stripping.…”

“…[183] Therefore, it is advantageous to design the expanding interlayer spacing of MXenes to increase their accessible surface area to electrolytes and improve the charge transport properties to obtain their complete charge storage capability. [184] Peng et al [176] have selected four diamine molecules of different sizes, ethylenediamine, 1,3-propanedinamine, 1,4-butanediamine and p-phenylenediamine as pillars to adjust the interlayer spacing of MXene. Such pillars also act as a crosslinking representative to homogeneously cross-link MXene to make hydrogels (denoted as EDA-MXene, PrDA-MXene, BDA-MXene, and PDA-MXene, respectively).…”

“…h) The XRD patterns of MXene and diamine-intercalated MXene, i) schematic representation of the ion transports. h,i) Reproduced with permission [176]. Copyright 2021, American Chemical Society.…”