Nanotip linear polyaniline grown at low voltage delivers record ion extraction for seawater desalination

Polyaniline, a notable polymer material, exhibits significant utility in electrical, optical, and thermal due to its unique reversible doping characteristics and physicochemical transformations. The efficiency of nitrogen-containing sites in polyaniline significantly influences its practical performance. This efficiency can be enhanced through molecular engineering by controlling the polymer's structure, degree of polymerization, and morphology. In this study, linear polyaniline with nanotips has been successfully synthesized via regulated voltage during electrochemical polymerization, achieving high-capacity ion extraction and desalination. Low-voltage polymerization eliminated dipolar cations, yielding products containing only quinonoid and benzenoid rings. Furthermore, the lower polymerization degree improved the efficiency of nitrogen-containing sites as electrochemical ion adsorption sites, resulting in a high chloride ion adsorption capacity of 339 mg g −1 and a sodium ion adsorption capacity of 142 mg g −1 . This research advances the development of structurally controllable materials and provides valuable insights into their design, particularly in terms of structural and morphological optimization.