Building durable aqueous K-ion capacitors based on MXene family

Abstract

Obtaining stable aqueous K-ion capacitors is still challenging due to the cathode materials tended to structurally collapse after long-term cycling during large-radius K-ion insertion/extraction. In this work, three different typical MXene electrodes, i.e., Nb 2 C, Ti 2 C, and Ti 3 C 2 were individually investigated upon their electrochemical behaviors for potassium-ion (K-ion) storage. All these MXene materials exhibited pseudocapacitive-dominated behaviors, fast kinetics, and durable K-ion storage, delivering superior performance compared with other K-ion host materials. According to the experimental results, it could be ascribed to the intrinsically large interlayer distance for K-ion transport and the superb structural stability of MXene even subjected to long-term potassiation/depotassiation process.

Novel Bimetallic Activated Center Alloying Mechanism Positive Electrodes for Aluminum Storage

“…[ 47 ] Additionally, the CV image of GO is also shown in Figure S7 in the Supporting Information, which presents a narrow rectangular curve, representing for limited electric double‐layer capacitance. [ 48–51 ] The rate capability of the Co 3 Sn 2 @GO composite was assessed at various current densities from 200 to 1000 mA g –1 . The positive electrode shows specific capacities as 130, 97, 84, 73, and 62 mAh g –1 at current densities of 200, 400, 600, 800, and 1000 mA g –1 , respectively.…”

In situ fabrication of MXene/CuS hybrids with interfacial covalent bonding via Lewis acidic etching route for efficient sodium storage

“…Fortunately, a new and large family of two-dimensional materials, namely MXenes, were rst synthesized by the HF etching of the MAX precursor in 2011 and have been a rising star in the eld of energy storage, as favored by their large interlayer spacing, abundant chemical composition, wonderful electrical conductivity, superb strain buffer capability, and ultralow diffusion barrier for alkali ions. [25][26][27][28] In particular, MXene are usually terminated by -O, -OH, -F, -Cl, and -S surface groups and various terminations would endow MXene with new and outstanding properties such as polar surface and superconductivity. [29][30][31][32] Therefore, based on the merits of MXene, it can be inferred that integrating CuS with MXene is benecial for rapid charge transfer, Na + ion migration, and structural robustness.…”

Delaminated V2C MXene Nanostructures Prepared via LiF Salt Etching for Electrochemical Applications

“…Numerous publications have demonstrated the metallic conductivity, − optical transparency, water dispersibility, thermal stability, − and hydrophilicity of MXenes. These properties make these materials excellent candidates for a variety of applications in energy storage, ,− catalysis, , electronics, and electromagnetic interference shielding. , …”