Giant Blue Energy Harvesting in Two‐Dimensional Polymer Membranes with Spatially Aligned Charges

Abstract

Blue energy between seawater and river water is attracting increasing interest, as one of the sustainable and renewable energy resources that can be harvested from water. Within the reverse electrodialysis applied in blue energy conversion, novel membranes with nanoscale confinement that function as selective ion transport mediums are currently in high demand for realizing higher power density. The primary challenge lies in constructing well‐defined nanochannels that allow for low‐energy‐barrier transport. In this work, we propose a concept for nanofluidic channels with a simultaneous dual electrostatic effect that can enhance both ion selectivity and flux. To actualize this, we have synthesized propidium iodide‐based two‐dimensional polymer (PI‐2DP) membranes possessing both skeleton charge and intrinsic space charge, which are spatially aligned along the ion transport pathway. The dual charge design of PI‐2DP significantly enhances the electrostatic interaction between the translocating anions and the cationic polymer framework, and a high anion selectivity coefficient (∼0.8) is reached. When mixing standard artificial seawater and river water, we achieve a considerable power density of 48.4 W m−2, outperforming most state‐of‐the‐art nanofluidic membranes. Moreover, when applied between the Mediterranean Sea and the Elbe River, an output power density of 42.2 W m−2 is achieved by the PI‐2DP. This nanofluidic membrane design with dual‐layer charges will inspire more innovative development of ion‐selective channels for blue energy conversion that will contribute to global energy consumption.This article is protected by copyright. All rights reserved

Promoting Volumetric Desalination Rate and Capacity via Highly Oriented, Densified Graphene Architectures

“…Water scarcity is one of the foremost challenges facing the world today. − Conventional seawater desalination technologies, including multieffect distillation, electrodialysis, and reverse osmosis, are constrained by their high energy consumption, costly maintenance, and inevitable membrane fouling, limiting their practical applications. − Capacitive deionization (CDI) stands out as an emerging technology for seawater desalination owing to its easy operation, low energy consumption, good regeneration, and environmental friendliness. , The CDI process involves electrochemical adsorption, wherein ions are stored in porous medium by applying a voltage on the electrode, purifying water by attracting ions from water . Electrode materials, as the core component of CDI, play a crucial role in achieving high-performance deionization capacity. − …”