In-situ synthesis of silver nanowire/carbonized wood sponge composites enabling rapid-response and robust mechanical performances for potential application in pressure sensors

Renewable biomass materials have found widespread application in manufacturing flexible pressure sensors by utilizing their distinctive 3D network with reversible compressibility and high sensitivity. However, biomass-derived sponges as pressure sensors often suffer from intrinsic limitations, including insufficient electrical conductivity, inadequate elastic recovery, and low electromechanical stability. To address these challenges, this work utilized renewable natural balsa wood with vertically aligned microchannels to construct a compressible and elastic 3D carbonized sponge (CWS) via sulfonation treatment and low-temperature carbonization. In situ synthesis strategy was then employed to integrate Ag-NWs into the CWS matrix, which synergistically enhanced both the electrical and mechanical properties of the CWS. The CWS sample of C-300 obtained at the carbonization of 300 °C exhibited a large compressible deformation range of 80%, withstanding pressures up to 150 kPa and maintaining stable mechanical performance over 100 compression stress-strain cycles. The prepared Ag NWs/CWS sensor demonstrated highly reversible compressibility, achieving a maximum sensitivity of 12.66 kPa⁻¹ and a low detection limit of 310 Pa. In addition, it can endure the strain range of 2–60% and keep sensing stability over 6000 cycles with a short response time of 100 ms. This work can provide a facile route to construct high performance pressure sensor from biomass materials, which has potential in real-time monitoring of human joint movements.