Piezoelectric sensors have attracted considerable attention due to their great potential in the smart wearable fields. However, their limited piezoelectric performance remains a critical bottleneck hindering their practical application. In this study, the heterogeneous cellular wall is constructed via a gradient fluorinated polyimide (FPI) impregnation strategy based on three-dimensional porous melamine foam (MF). The composite heterogeneous interfaces integrate the triboelectric effect within the porous skeleton, resulting in a synergistic piezoelectric-triboelectric effect and promote the mechanical-electrical conversion ability of the sensor. This coupling effect significantly improves electrical output performance up to 52 V with excellent gas permeability and fast recovery speed (22 ms). Moreover, the composite demonstrates superior sensitivity (1.34 V·kPa −1) and exceptional durability (>10,000 cycles) as a pressure sensor, suitable for detecting diverse human activities. In addition, a self-powered smart warning sleeve with signal transmission capabilities was developed by integrating portable MF/FPI sensors with electronic components. This work proposes an innovative strategy for designing advanced and resilient self-powered microelectric devices.