Fabrication of Fe nanocomplex pillared few-layered Ti₃C₂T_x MXene with enhanced rate performance for lithium-ion batteries

Pillaring technologies have been considered as an effective way to improve lithium storage performance of Ti₃C₂T_x MXene. Nevertheless, the pillared hybrids suffer from sluggish Li⁺ diffusion kinetics and electronic transportation due to the compact multi-layered MXene structure, thus exhibiting inferior rate performance. Herein, the few-layered Ti₃C₂ MXene (f-Ti₃C₂ MXene) which is free from restacking can be prepared quickly based on the NH₄⁺ ions method. Besides, Fe nanocomplex pillared few-layered Ti₃C₂T_x (FPTC) heterostructures are fabricated via the intercalation of Fe ions into the interlayer of f-Ti₃C₂ MXene. The f-Ti₃C₂ MXene which is immune to restacking can provide a highly conductive substrate for the rapid transport of Li⁺ ions and electrons and possess adequate electrolyte accessible area. Moreover, f-Ti₃C₂ MXene can efficiently relieve the aggregation, prevent the pulverization and buffer the large volume change of Fe nanocomplex during lithiation/delithiation process, leading to enhanced charge transfer kinetics and excellent structural stability of FPTC composites. Consequently, the FPTC hybrids exhibit a high capacity of 535 mAh·g⁻¹ after 150 cycles at 0.5 A·g⁻¹ and an enhanced rate performance with 310 mAh·g⁻¹ after 850 cycles at 5 A·g⁻¹. This strategy is facile, universal and can be extended to fabricate various few-layered MXene-derived hybrids with superior rate capability.