A thin, intrinsically stretchable MXene-MWCNTs/polymer current collector for deformable aqueous Li-ion batteries

Abstract

Stretchable current collectors are essential components of deformable energy-storage devices. Deposition of a conductive layer on an elastomer surface is a common fabrication strategy for stretchable current collectors, however, facing the challenges of reducing the tensile resistance and film thickness. In this study, by integrating Ti₃C₂T_x nanosheets with MWCNTs, the authors deposited a staggered conductive network on the surface of an elastic styrene–ethylene–butylene–styrene (SEBS) film and thus created a stretchable hybrid conductor (TMS). The TMS current collector exhibits a low sheet resistance of about 31.3 Ω □⁻¹ and shows relatively minor changes under stretching states. The current collector with a thickness of 144 μm possesses a strain ability of 100% and can recover to the original state when the stress is withdrawn. Besides, the TMS-based coin cell using V₂O₅ and LiMn₂O₄ as active materials achieves a reversible capacity of 85.5 mA h g⁻¹ and delivers a high capacity retention of 95.4% (5C, 900 cycles), comparable to performance with the traditional rigid Ti current collectors (97.1%). Furthermore, the assembled coplanar batteries with a thickness of 366 μm can work under bending and stretching states with stable electrochemical performance. Moreover, the power supply tests under various working states demonstrated the ability of the stretchable LIBs to deliver stable power to a red LED, which shows a promising approach for developing thin and deformable energy-storage systems.