Capacitive deionization (CDI) based on electrosorption has been considered a new type of environmentally friendly desalination technology and has been favored by researchers due to its low energy consumption, high efficiency, no secondary pollution, and sustainability. This paper characterizes the CDI knowledge landscape by identifying and visualizing collaboration networks, reference co-citation networks, and keyword co-occurrence networks through a scientometric analysis of academic papers on CDI between 2009 and 2023. The results show that the number of papers in this area has increased exponentially and has become an increasingly interdisciplinary research topic. We have made it clear that the current research hotspots in CDI mainly focus on desalination performance, Faraday electrode materials, CDI cell design, and desalination mechanism analysis. In addition, we propose some current problems and future research directions for CDI, hoping to guide upcoming CDI research.