Ti₃C₂T_x MXene Conductive Layers Supported Bio‐Derived Fe_x−1Se_x/MXene/Carbonaceous Nanoribbons for High‐Performance Half/Full Sodium‐Ion and Potassium‐Ion Batteries

Abstract

widely used alkali metal; however, it will be likely replaced with other alkali elements in the foreseeable future due to the limited Li reserves in the Earth's crust. [2] Therefore, the development of next-generation cost-effective sustainable energy storage system represents an urgent task. Sodium and potassium metals with relatively large ionic radii and electronic structures similar to that of Li have become promising candidates as the anode materials of alkali-metal-ion batteries because of their abundant reserves, high theoretical capacities, and low redox potentials close to Li + /Li. [3,4] Unfortunately, the high repulsive forces generated during the ion insertion and extraction processes occurring in sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) significantly limit their large-scale commercial applications. Therefore, it is necessary to identify suitable host materials for the both the larger sodium ions (Na + ) and potassium ions (K + ).The convergence of biological and synthetic materials is a cutting-edge subject that offers significant potential to develop bionic hybrid materials with improved properties, especially in the context of energy storage. [5,6] With unique functions, the 1D hierarchical nanostructure is one of the most promising type of high efficiency materials. This type of Owing to their cost-effectiveness and high energy density, sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) are becoming the leading candidates for the next-generation energy-storage devices replacing lithiumion batteries. In this work, a novel Fe x−1 Se x heterostructure is prepared on fungus-derived carbon matrix encapsulated by 2D Ti 3 C 2 T x MXene highly conductive layers, which exhibits high specific sodium ion (Na + ) and potassium ion (K + ) storage capacities of 610.9 and 449.3 mAh g −1 at a current density of 0.1 A g −1 , respectively, and excellent capacity retention at high chargedischarge rates. MXene acts as conductive layers to prevent the restacking and aggregation of Fe x−1 Se x sheets on fungus-derived carbonaceous nanoribbons, while the natural fungus functions as natural nitrogen/carbon source to provide bionic nanofiber network structural skeleton, providing additional accessible pathways for the high-rate ion transport and satisfying surfacedriven contribution ratios at high sweep rates for both Na/K ions storages. In addition, in situ synchrotron diffraction and ex situ X-ray photoelectron spectroscopy measurements are performed to reveal the mechanisms of storage and de-/alloying conversion process of Na + in the Fe x−1 Se x /MXene/carbonaceous nanoribbon heterostructure. As a result, the assembled Na/K full cells containing MXene-supported Fe x−1 Se x @carbonaceous anodes possess stable large-ion storage capabilities.

Electrolyte formulation strategies for potassium‐based batteries

“…0 1 -3 [46] Fe x−1 Se x /MXene/FCR 0.8 M KPF 6 in EC/DMC = 1 67.7% after 2000 cycles (10A g −1 ) 0 . 0 1 -3 [47] Ultrasmall CoP nanoparticles 0.8 M KPF 6 in EC/DEC = 1 74.3% after 2800 cycles (100 mA g −1 ) 0 . 0 1 -3 [48] Antimony (Sb) 4.0 M KFSI in DME 95.4% after 200 cycles (200 mA g −1 ) 0 .…”

TiVCTx MXene/Chalcogenide Heterostructure‐Based High‐Performance Magnesium‐Ion Battery as Flexible Integrated Units

“…Meanwhile, the binding energy of Se 3d at ≈56 eV was upshifted, signaling the novel bonding behavior of NiSe 2 , or CoSe 2 or both during Mg 2+ de-/insertion. [24,[32][33][34] We conducted ex situ SEM tests on the electrode surface at the fully discharged state before and after 100 cycles (Figure 4g,h) to further verify the reversibility of the assembled MIBs based on the proposed NCSe@TiVC heterostructure during the cycling process in terms of the morphological changes in the NCSe@TiVC heterostructure cathode and metallic Mg anode. 3D spherical structure of NCSe@TiVC heterostructure was well-reserved after 100 charging/discharging cycles with only a mild variation in detailed surface morphology, indicating the excellent structural stability of the composites.…”

A two-dimensional MXene/BN van der Waals heterostructure as an anode material for lithium-ion batteries

“…1,2 It is well known that Ti 3 C 2 T x is produced by selectively removing Al atoms from the Ti 3 AlC 2 phase, which generates abundant surface functional groups on the surface of MXene. 3,4 Although the terminal groups on the surface of Ti 3 C 2 T x are beneficial for interfacial self-assembly, they result in low specific capacity and rate capability. 5 Moreover, it also suffers from the restacking of the MXene nanosheets owing to interlayer van der Waals forces and hydrogen bonds.…”