Hydrovoltaic energy harvesting: A systematic review and bibliometric analysis of technological innovations, research trends, and future prospects

The growing demand for sustainable energy solutions has positioned hydrovoltaic energy harvesting (HEH) as a promising renewable technology that converts water-based phenomena into electricity. Despite its potential, the field lacks a comprehensive synthesis of its research progress and technological evolution. This study addresses this gap through an integrated bibliometric and systematic review approach. Bibliometric analysis of 52 peer-reviewed articles, sourced via Scopus, reveals an exponential growth in HEH research from 2020 to 2024, driven predominantly by East Asian countries, with China leading the field. Key thematic clusters were identified using tools such as Bibliometrix and VOSviewer, highlighting innovations in materials like MXenes and nanostructured carbon and their role in enhancing energy conversion efficiency. A systematic review of the selected studies categorizes advancements in fundamental mechanisms, device architecture, and scalable applications. Notable findings include the development of flexible hydrovoltaic devices for wearable electronics and hybrid systems for integrated energy generation and storage. These advancements underline HEH's potential for addressing climate challenges and energy inequities, particularly in underrepresented regions like Africa and South America. The review highlights strategic investment priorities for HEH systems, including scaling, integrating hybrid technologies, and fostering global collaborations to accelerate HEH's transition to practical, scalable renewable energy systems.