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High‐performance fibrous materials urgently desired for fabricating energy storage devices to power wearable textile electronics are expected excellent mechanical properties, improved output capacitance, and rapid charge/discharge capability; nevertheless, their contradictory requirements in material design impose immense challenges. Inspired by the robust structure of higher plants that evolve over millions of years, herein, an interfacial engineering strategy is proposed for synergizing the mechanical strength and electrochemical performance of Ti3C2TX MXene fibers by selecting aramid (Kevlar) nanofibers and borate ions (B) as the enhancers. The intercalation of Kevlar nanofibers endows the nascent wet‐spun MXene gel fibers with a high stretchable ratio through physical interaction (hydrogen bonds), greatly aligning the orientation of MXene nanosheets. B‐cross‐links introduce covalent bonds between MXene nanosheets, which together with hydrogen bonds significantly enhance fiber strength. More importantly, optimal ion transport kinetics is achieved by synergizing the inverse impacts of Kevlar nanofibers and B‐cross‐link on interlayer spacing, guaranteeing excellent electrochemical performances. Benefiting from their excellent mechanical, electrical, and electrochemical performances, borate (B)‐cross‐linked MXene/Kevlar fibers (MKB) are simultaneously adopted as fibrous electrodes and receiving antennae for asymmetric supercapacitors with wireless charging functions. The proposed strategy provides an avenue for designing high‐performance functional fibers for future wearable applications. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Designing a thick electrode with appropriate mass loading is a prerequisite toward practical applications for lithium ion batteries (LIBs) yet suffers severe limitations of slow electron/ion transport, unavoidable volume expansion, and the involvement of inactive additives, which lead to compromised output capacity, poor rate perforamnce, and cycling instability. Herein, self-supported thick electrode composed of vertically aligned two-dimensional (2D) heterostructures (V-MXene/V 2 O 5 ) of rigid Ti 3 C 2 T X MXene and pliable vanadium pentoxide are assembled via an ice crystallization-induced strategy. The vertical channels prompt fast electron/ion transport within the entire electrode; in the meantime, the 3D MXene scaffold provides mechanical robustness during lithiation/delithiation. The optimized electrodes with 1 and 5 mg cm -2 of V-MXene/V 2 O 5 respectively deliver 472 and 300 mAh g -1 at a current density of 0.2 A g -1 , rate performance with 380 and 222 mAh g -1 retained at 5 A g -1 , and reliability over 800 charge/discharge cycles.

Prussian blue analogues (PBAs) are believed to be intriguing anode materials for Li + storage because of their tunable composition, designable topologies, and tailorable porous structures, yet they suffer from severe capacity decay and inferior cycling stability due to the volume variation upon lithiation and high electrical resistance. Herein, we develop a universal strategy for synthesizing small PBA nanoparticles hosted on two-dimensional (2D) MXene or rGO (PBA/MX or PBA/rGO) via an in situ transformation from ultrathin layered double hydroxides (LDH) nanosheets. 2D conductive nanosheets allow for fast electron transport and guarantee the full utilization of PBA even at high rates; at the meantime, PBA nanoparticles effectively prevent 2D materials from restacking and facilitate rapid ion diffusion. The optimized Ni 0.8 Mn 0.2 -PBA/MX as an anode for lithium-ion batteries (LIBs) delivers a capacity of 442 mAh g -1 at 0.1 A g -1 and an excellent cycling robustness in comparison with bare PBA bulk crystals. We believe that this study offers an alternative choice for rationally designing PBA-based electrode materials for energy storage.