Inkjet printed Ti3C2T -based temperature sensor for external monitoring of batteries

Inkjet printing represents a versatile, maskless and cost-effective approach for the fabrication of flexible electronic devices, enabling the deposition of functional materials on diverse substrates. In this work, we demonstrate the use of conductive additive-free Ti₃C₂Tₓ MXene as a resistive sensing material for inkjet-printed temperature sensors directly integrated onto the external case of lithium-ion batteries. Ti₃C₂Tₓ MXene was synthesized and formulated into a stable water-based ink suitable for inkjet printing. The printed films exhibited uniform morphology, excellent adhesion on polyethylene terephthalate (PET) substrates after polyethyleneimine (PEI) treatment and stable electrical behavior. The resistive response of the sensors displayed a clear negative temperature coefficient (NTC) behavior, with a temperature coefficient of resistance (TCR) up to −1.3% °C⁻¹ in the range 20–60 °C, depending on film thickness and initial resistance. When printed on a Li-ion battery casing, the Ti₃C₂Tₓ-based sensors reliably tracked temperature variations during multiple charge–discharge cycles at different C-rates, maintaining stable and reproducible performances. These results highlight the potential of conductive additive-free MXene inks and inkjet printing as an effective strategy for the scalable fabrication of flexible temperature sensors for battery health monitoring and safety management. • A water-based, inkjet-printable Ti₃C₂Tₓ MXene ink enables maskless temperature sensor fabrication. • Inkjet-printed Ti₃C₂Tₓ films show uniform morphology, strong adhesion on PEI-treated PET and stable NTC behavior (TCR up to −1.3% °C⁻¹). • Sensor sensitivity is tuned by controlling the initial resistance via the number of printed layers. • Direct printing on lithium-ion battery casings enables reliable temperature monitoring during charge–discharge cycles.