Electrostatically Fabricated Three-Dimensional Magnetite and MXene Hierarchical Architecture for Advanced Lithium-Ion Capacitors

Abstract

Conversion-type magnetite shrewdly shows abundance, nontoxicity, and high lithium storage capacity. However, either pristine magnetite or nanocomposites with two-dimensional materials cannot prevent restacking, pulverization, and poor structural homogeneity simultaneously because of a lack of universal interfacial interactions. Here, an electrostatic self-assembly strategy is uncovered between hollow Fe 3 O 4 /C microspheres (with H + -induced quasiintrinsic positive charge) and few-layer MXenes (with intrinsic negative charge from terminating functionalities). This strategy realizes the uniform and interconnected architecture of Fe 3 O 4 /C@MXene that favors fast Li + diffusion, easy electron/charge transfer, and suppressed pulverization. Specifically, after the long-term cycling, an undegraded specific capacity of 907 mA h g −1 remains at 0.5 A g −1 . Further adoption of such superior anode in 4.0 V lithium-ion capacitors results in a high energy density of 130 W h kg −1 , a maximum power density of 25,000 W kg −1 , and excellent cycling stability. This work thus sheds light on a generic self-assembly process where intrinsic electrostatic interaction plays an essential role.

Interface-Engineered Fe3O4/MXene Heterostructures for Enhanced Lithium-Ion Storage

“…The Fe 3 O 4 /MXene-7 was capable of delivering a reversible capacity of 554.1 mAh g −1 in the initial cycle with a maintained capacity of 667.9 mAh g −1 and a Coulombic efficiency of 100.0% after 600 cycles, indicating its excellent cycling stability. Figure 4e depicts the generalized ternary plot showing the comparison of lithium storage performances for Fe 3 O 4 /MXene-7 with other reported MXene/iron oxide hybrids, 34,35,47,49−51 such as C-coated Fe 3 O 4 @Ti 3 C 2 -2.5 (343 mAh g −1 at 500 mA g −1 ), 34 Fe 3 O 4 @ Ti 3 C 2 -2:5 (278.3 mAh g −1 at 1250 mA g −1 ), 35 Fe 3 O 4 /C@ MXene (493 mAh g −1 at 1000 mA g −1 ), 50 and Fe 2 O 3 /N-Ti 3 C 2 (688 mAh g −1 at 100 mA g −1 ), 51 where Fe 3 O 4 /MXene-7 exhibits superior lithium storage properties in terms of specific capacity, rate performance, and cycling stability (Table S1).…”

Microbe-Assisted Assembly of Ti3C2Tx MXene on Fungi-Derived Nanoribbon Heterostructures for Ultrastable Sodium and Potassium Ion Storage

“…As observed in Figure S5a, the adsorption quantity of MXene@NCRib sharply increases when the relative pressure reaches the saturation vapor pressure, while the isotherms of fungi-derived carbonaceous nanoribbon only slightly increase with the increasing relative pressure, which can be considered as a proof of the good distribution of 2D MXene nanosheets on 1D carbonaceous nanoribbons. The calculated specific surface area is 26.96 m 2 g –1 , and most pores are 2–10 nm, which suggests the mesoporous nature of MXene@NCRib …”

“…The calculated specific surface area is 26.96 m 2 g −1 , and most pores are 2−10 nm, which suggests the mesoporous nature of MXene@NCRib. 24 The microstructure of MXene@NCRib was further characterized through TEM and high-resolution TEM techniques. In Figure 1d, the core−shell hybrid structure is clearly observed, where wrinkled Ti 3 C 2 T x nanosheets are attached on the inner nanoribbons.…”

Self-assembled multifunctional Fe3O4 hierarchical microspheres: high-efficiency lithium-ion battery materials and hydrogenation catalysts

“…Here, the low R ct was beneficial to the enhancement of the electron kinetics and the diffusivity of the lithium ions in the electrode materials [40,41]. The high capacity and ultralong cycle life for Fe 3 O 4 HMSs, which was applied in LIB, should be due to the following reasons: (i) the self-assembled hierarchical microstructures composed of nanoparticle (inner) and nanoplate (outer) subunits availed more contact positions for the electrolyte and Li + [52][53][54][55][56][57]; (ii) the self-assembled hierarchical architecture based on the nanoparticle (inner) and nanoplate (outer) units optimized the electrochemical reaction kinetic process [26][27][28]52,53], which facilitated the fast diffusion of Li + ; and (iii) the self-assembled hierarchical microstructures resisted the huge volume changes that occurred during the Li + -insertion/extraction processes [26][27][28]52,53].…”