Hydrothermal Self-Assembly of α-MnSe-Loaded Honeycomb-Like Biomimetic Ti₃C₂T_x/Graphene Aerogel Microstructure (α-MnSe/Ti₃C₂T_x/rGO) as Efficient Electrode Material for Energy Storage Application

Abstract

Recently, metal selenides have gathered considerable attention for use as electrode materials for supercapacitor applications because of their substantial theoretical capacities. However, sluggish ion transport and chemical or mechanical degradation of electrode materials during continuous operation severely hamper their electrochemical performance. Herein, we have assembled MnSe (∼10−12 nm) into a 3D Ti 3 C 2 T x /rGO aerogel scaffold with bimodal pore size distribution through a low temperature hydrothermal method, followed by freeze-drying. A 3D percolation network of as-prepared MnSe/Ti 3 C 2 T x /rGO aerogel (MnSe/TCGA) improved electrolyte penetration by providing multidimensional ion transmission channels. High intrinsic conductivity of Ti 3 C 2 T x in combination with rGO facilitated electronic transport during electrochemical activity. Cellular sieves of the MnSe/ TCGA aerogel scaffold effectively interlocked MnSe particles and thereby prevented pulverization and aggregation of active material. Consequently, a MnSe/TCGA electrode with a specific architecture exhibited a significant specific capacity of 225.4 mAh/g at 1 A/g and maximum initial Coulombic efficiency of 99.5%, which surpassed the values obtained for its counterparts (i.e., MnSe/GA and MnSe). Furthermore, MnSe/TCGA showed an excellent rate capability (158 mAh/g at 12 A/g) and a superb life span (92.1% over 5000 cycles). When examined through impedance studies, MnSe/TCGA revealed low series and charge transfer resistances (R s = 2.6 Ω and R CT = 5.2 Ω). Overall, as-obtained findings provide insight on constructing high performance 3D porous and hybrid microstructures to optimize electrochemical energy storage performance.

Boosting Manganese Selenide Anode for Superior Sodium-Ion Storage via Triggering α → β Phase Transition

“…Rietveld refinement XRD patterns of α–α-MnSe (Figure a) and δ−α-MnSe (Figure b) can be indexed as cubic α-MnSe structure with the space group of Fm 3̅ m , , and the detailed refinement results are shown in Tables S1 and S2, illustrating that both α-MnSe materials possess close lattice parameters. Raman spectra in Figure c display the characteristic peak of α-MnSe at 645.7 cm –1 , and two weak peaks located at 1345.8 and 1555.0 cm –1 are assigned to sp 3 hybrid disordered carbon (D-band) and sp 2 hybrid graphite carbon (G-band). , In order to elucidate the detailed difference between α–α-MnSe and δ−α-MnSe, electron paramagnetic resonance (EPR) was conducted as shown in Figure d, suggesting that α–α-MnSe exhibits much higher content of Se vacancies than δ−α-MnSe. , N 2 adsorption–desorption isotherms in Figure S5 reveal type-IV curves with H3 hysteresis loops, which manifests that the porous structure of both α-MnSe materials is composed of interstices between nanorods.…”

Integration of Polymorphic CoxSey on MXene-Incorporated Self-Templated Three-Dimensional Graphene Foam to Augment Supercapacitor Performance through Componential and Structural Modifications

“…Capacity fading is observed at high current densities, with the specific capacity approaching its least values of 43.3, 96.6, and 178 mAh g –1 at 12 A g –1 for Co x Se y , Co x Se y @rGOF, and Co x Se y @TC/rGOF, respectively. A decrease in specific capacity with the enhancement in applied current density is due to the time constraints applied to the charge storage processes where the electrolyte ions do not find enough time to reach the electroactive sites for the energy storage process . Hence, a decrease in specific capacity is usually observed at high current densities.…”

“…A decrease in specific capacity with the enhancement in applied current density is due to the time constraints applied to the charge storage processes where the electrolyte ions do not find enough time to reach the electroactive sites for the energy storage process. 56 Hence, a decrease in specific capacity is usually observed at high current densities. Co x Se y @TC/rGOF maintained 73.2% of initial specific capacity as compared to Co x Se y @rGOF (65.6%) and Co x Se y (54.5%) at a 12 times increase in current density.…”