Citation

Xinyue Zhang, Baohu Wu, Huiqing Wu*, and Peiyi Wu*. Engineering multiscale heterostructure as ionic diode and light-driven ion pump for osmotic-solar energy harvesting. CCS Chem. 2024, ASAP.

Abatract

As blue energy, osmotic power holds tremendous potential for electricity generation via membrane-based reverse electrodialysis. However, current processes suffer from low energy output, mainly due to the inadequate transmembrane ion transport and polarization phenomenon. Inspired by plant growth and photosynthesis, we propose a robust heterogeneous membrane that enables ionic-diode rectified and light-enhanced ion transport for efficient osmotic-solar energy harvesting. The membrane is rationally constructed by in-situ growth of polyaniline onto a sulfonated matrix, creating a multiscale heterostructure that enables the coexistence of a Janus-like architecture and semiconductor heterojunction. Benefiting from multi-asymmetries of geometry, charge and chemistry, the membrane delivers a high unidirectional ion flow and suppresses polarization, generating an exceptional osmotic power density up to 12.6 W m−2 at 50-fold salinity gradient. Light-driven ion pumping is achieved by the synergistic photothermal and photoelectric effect of the polyaniline heterojunction. Under light irradiation, temperature gradient and transmembrane potential are triggered simultaneously, accelerating ion movement and thus elevating energy conversion output. This work pioneers the development of high-performance power generators capable of harnessing energy from diverse salty sources coupled with solar resource.