Flexible Pressure Sensors with Dual Conductive Networks Based on Carbon Nanotube-Graphene Nanosheet Composites

In recent years, flexible piezoresistive pressure sensors have attracted widespread attention due to their simple structure, ease of manufacture, and ease of signal acquisition. However, achieving both high sensitivity and a wide response range in sensors remains a major challenge. It is worth noting that we have proposed an integrated gradient porous structure with a dual conductive network. The structure consists of a low-modulus porous foam layer and a high-modulus porous fiber layer. This structural design enables each layer of the sensor to have unique pressure-sensing capabilities. In addition, the introduction of a dual conductive network increases contacts between conductive fillers, creating more conductive paths, improving conductivity and sensitivity, and further optimizing sensor performance. The sensor has high sensitivity (S = 2.35 kPa–1) at low pressure (0–26 kPa), a wide sensing range (0–150 kPa), fast response time (98 ms), and excellent stability with over 6000 dynamic cycles. This innovative dual-conductive network integrated gradient porous structure not only improves pressure-sensing performance but also provides a solution for designing advanced flexible piezoresistive sensors. In addition, we conducted a series of application tests based on TPU/CNT-TPU/GNP sensor, proving that the sensor we proposed has broad application prospects in fields such as human motion monitoring and wearable smart devices.