A three-in-one Ti3C2Tx MXene additive for low-temperature ultrathick electrodes
Ultrathick electrodes are pivotal for high mass loading and energy density, particularly in cold climates. Conventional electrode fabrication using slurry coating suffers from critical cracking thickness limitations and sluggish ion transport, while 3D printing demands rheologically suitable inks. Existing additives—polymer binders, conductive agents—compromise active content and electrochemical performance. This work introduces Ti3C2Tx MXene as a three-in-one additive functioning simultaneously as viscosifier, conductive agent, and active material. Highly concentrated MXene gel exhibits shear-thinning behavior enabling 3D printing of electrodes up to 1 mm thick. The multi-scale porous architecture facilitates rapid ion transport. A 3D-printed MoS3/MXene electrode achieves mass loading up to 18.4 mg cm−2 and areal capacity of 7.2 mA h cm−2, retaining 4.2 mA h cm−2 at −20 °C. A full cell with MoS3/MXene anode and Na3V2(PO4)3/MXene cathode delivers 400 Wh kg−1 energy density. This multifunctional MXene strategy addresses the trade-off between active content, printability, and low-temperature performance, offering a viable route for high-energy-density sodium-ion batteries in cold environments.