Mechanically superior MXene/PBONF-PSS membrane with adjustable surface charge for ultrahigh osmotic energy harvesting towards extremely complex conditions

Osmotic energy has emerged as a highly promising renewable energy source due to its abundant reserves, environmental sustainability, and widespread availability. While the influences of conventional environmental factors such as temperature and pH on the performance of osmotic energy conversion membranes have been extensively studied, their performance and stability under harsh mechanical conditions, such as ultrasonic vibration, puncture, and stretching, remain poorly understood. To overcome this limitation, we developed innovative MXene/poly( p -phenylene-benzodioxazole) nanofibers (PBONF)-polystyrene sulfonate (PSS) (MXP-PSS) composite membranes by integrating rigid PSS-functionalized PBONF with negatively charged MXene nanosheets using a precisely regulated surface charge modification and interfacial engineering strategy. The resulting membrane exhibits exceptional mechanical properties with a longitudinal tensile strength of 299.27 ± 8.20 MPa and transverse puncture resistance of 1057.65 KPa, which is far superior to that of pure MXene membranes, as corroborated by finite element simulation. More importantly, the membrane demonstrates superior osmotic energy conversion performance, achieving peak power densities of 15.18 W/m 2 and 67.57 W/m 2 under 50-fold and 500-fold salinity gradients, respectively, while maintaining excellent ion selectivity (0.87 and 0.79) . Notably, the membrane retains stable power generation even under extreme conditions including ultrasonic vibration, mechanical stretching, and wide pH ranges , demonstrating unprecedented environmental durability. This work presents a breakthrough in developing highly mechanical, charge-tunable nanofluidic membranes for efficient osmotic energy harvesting in complex environments.