MXene-Intercalated GO/MnO₂ via Layer-by-Layer Assembly for Highly Sensitive Wearable Capacitive Microsensors

The convergence of energy storage and sensing functionalities in a single miniaturized device represents a critical advancement for next-generation wearable electronics. Herein, we report an MXene/GO@MnO2 composite with a rationally designed layer-by-layer architecture for planar microsupercapacitors (PMSCs) and capacitive microsensors. By intercalating MnO2-decorated graphene oxide (GO@MnO2) between MXene layers, the interlayer spacing is expanded to 1.47 nm, enabling ultrafast ion diffusion (DLi+ = 3.1 × 10–12 cm2 s–1) and efficient vertical electron transport (σ⊥ = 247.7 S m–1). The resulting PMSCs achieve record-high areal capacitance (39.3 mF cm–2) and energy density (2.0 μWh cm–2) among MXene-based microdevices, with 91.1% capacitance retention after 10,000 cycles. As a wearable sensor, the device demonstrates multisignal detection capability, including temperature (10–40 °C, sensitivity = 6.3% °C–1), pressure (sensitivity >1.0 kPa–1, response time <10 ms), and biomechanical motions. This work provides a paradigm for designing multifunctional microsystems through strategic interlayer engineering of 2D materials.