Co₂V₂O₇@Ti₃C₂T_x MXene Hollow Structures Synergizing the Merits of Conversion and Intercalation for Efficient Lithium Ion Storage

Abstract

Rechargeable batteries are deemed as green and efficient energy storage systems and have drawn great attention during past decades. Despite the commercial applications of lithium‐ion batteries, the ever‐increasing demands for higher energy storage capability driven by the rapid development of portable/wearable electronics remain unsatisfied due to the low theoretical capacity of the commonly used graphite anode. Herein, a material design strategy by synergizing the merits of conversion‐type Co2V2O7 and intercalation‐based Ti3C2Tx MXene for efficient lithium‐ion storage is reported. The Co2V2O7@MXene hollow polyhedrons are synthesized by ion exchange, surface modification, and the subsequent electrostatic assembly. Benefiting from the high conductivity and mechanical robustness of the MXene sheath, the high theoretical capacity of Co2V2O7, and the unique hollow structure, the optimized hybrids deliver a high output capacity of 949.7 mAh g−1 at 0.1 A g−1, excellent rate capacity with 431.4 mAh g−1 retained at 5.0 A g−1, as well as outstanding cycling stability.

V2CTx MXene-Encapsulated Liquid Metal Composite as an Anode for Wide-Temperature Li-Ion Batteries

“…14 Sun and co-workers developed a Co 2 V 2 O 7 /MXene composite anode for LIBs which delivered a specific capacity of 949.7 mA h g −1 at 0.1 A g −1 . 15 In our previous work, the terminal groups of Ti 3 C 2 T x MXene can be tuned by simple heat treatment, which a specific capacity of 404 mA h g −1 even after 500 cycles was achieved. 16 In contrast to Ti 3 C 2 T x , which has five atomic layers, V 2 CT x MXene possesses fewer layers (three atomic layers), providing more favorable channels for lithium ion transport.…”

“…Two-dimensional (2D) MXene materials have been investigated as anode for LIBs and displayed superior rate performance due to their large layer distance which facilitates fast ionic transportation. − Tremendous efforts have been devoted to regulating the material structure and optimizing the composition of electrode materials to further improve the reversible Li storage performance . Sun and co-workers developed a Co 2 V 2 O 7 /MXene composite anode for LIBs which delivered a specific capacity of 949.7 mA h g –1 at 0.1 A g –1 . In our previous work, the terminal groups of Ti 3 C 2 T x MXene can be tuned by simple heat treatment, which a specific capacity of 404 mA h g –1 even after 500 cycles was achieved .…”

Nacre-Inspired Strong MXene/Cellulose Fiber with Superior Supercapacitive Performance via Synergizing the Interfacial Bonding and Interlayer Spacing

“…Among all accessible nanomaterials for the fabrication of advanced fibers, Ti 3 C 2 T X MXene with a two-dimensional micrometer-scale layered structure possesses the advantageous features of high volumetric capacitance originating from the rapid surface redox reactions, high mechanical strength, and metallic conductivity. Moreover, the hydrophilic surface groups (e.g., −F, −OH, and −O) on both sides of nanosheets enable Ti 3 C 2 T X MXene to be suitable for solution processing. − Benefiting from the aforementioned merits, MXene fibers have been successfully prepared via the techniques of wet-spinning, − 3D printing, and biscrolling. , For instance, by extruding the MXene dispersion through a coagulation bath, the negatively charged Ti 3 C 2 T X nanosheets automatically assemble into a continuous fiber via restacking. However, thus-spun 100 wt % MXene fibers typically suffer from low mechanical strength and poor rate performance because of the weak interfacial bonding and the restacking between Ti 3 C 2 T X nanosheets. − In principle, the compactness and interlayer interaction are two vital parameters that should be considered for the design of strong fibers.…”