Bismuth Nanoparticle-Embedded Porous Carbon Frameworks as a High-Rate Chloride Storage Electrode for Water Desalination

Capacitive deionization (CDI) is a promising cost-effective and low energy consumption technology for water desalination. However, most of the previous works focus on only one side of the CDI system, i.e., Na+ ion capture, while the other side that stores chloride ions, which is equally important, receives very little attention. This is attributed to the limited Cl– storage materials as well as their sluggish kinetics and poor stability. In this article, we demonstrate that a N-doped porous carbon framework is capable of suppressing the phase-transformation-induced performance decay of bismuth, affording an excellent Cl– storage and showing potential for water desalination. The obtained Bi-carbon composite (Bi/N-PC) shows a capacity of up to 410.4 mAh g–1 at 250 mA g–1 and a high rate performance. As a demonstration for water desalination, a superior desalination capacity of 113.4 mg g–1 is achieved at 100 mA g–1 with excellent durability. Impressively, the CDI system exhibits fast ion capturing with a desalination rate as high as 0.392 mg g–1 s–1, outperforming most of the recently reported Cl– capturing electrodes. This strategy is applicable to other Cl– storage materials for next-generation capacitive deionization.