Metal-organic framework/Ti2VC2Tx@polydopamine (PDA) derived functional nanostructures for lithium-ion batteries with ultra-high stability at low temperatures

Two-dimensional transition metal carbides (MXenes) are limited in their practical application in lithium-ion batteries due to their inherent interlayer stacking and susceptibility to oxidation. In order to address this challenge, a three-dimensional porous CZIF-67/Ti 2 VC 2 T x @polydopamine (PDA) composite material was successfully constructed through electrostatic self-assembly and in-situ carbonisation strategies in this study. This composite material, when utilised as the anode in lithium-ion batteries, exhibits remarkable electrochemical performance. In the half-cell, the initial reversible capacity is 857.6 mAh g −1 (0.1 A g −1 ). Following 900 cycles at an elevated current density of 1 A g −1 , the capacity remains at 402.6 mAh g −1 , with a capacity retention ratio of 88.25 %. It is particularly noteworthy that this electrode exhibits remarkable adaptability across a broad temperature range. Following 100 cycles at −25 °C, the capacity was determined to be 385.2 mAh g −1 (0.1 A g −1 ), and at 60 °C, the capacity was as high as 1486.3 mAh g −1 (0.1 A g −1 ). The reversible capacity of the assembled CZIF-67/Ti 2 VC 2 T x @PDA//LiFePO 4 full cell was stabilized at 467.7 mAh g −1 after 100 cycles at 0.1C. This significant enhancement in performance can be attributed to its unique three-dimensional network structure, which has been demonstrated to accelerate ion and electron transport, whilst also providing effective structural protection and volume buffering. This research proposes a novel approach for the design of high-performance, wide-temperature-range bimetallic MXene-based composite electrode materials.