Tungsten Diselenide <scp>WSe₂</scp>@<scp>PVP</scp> Polymer Composite Supercapacitors: Development of Energy Storage Capabilities

ABSTRACT In our research, we have introduced an innovative approach to preparing a composite material for tungsten diselenide (WSe 2 ) with polyvinyl pyrrolidone (PVP), demonstrating an improvement in the performance of electrochemical applications. The interaction between WSe 2 and PVP serves multiple functions, such as acting as a surface stabilizer, reducing agent, dispersant of nanoparticles, and growth modifier. This significantly enhances electrolyte penetration and improves the electrochemical efficiency in devices like supercapacitors. Our investigation unveils a simple yet effective hydrothermal method for synthesizing a bare WSe 2 and WSe 2 @PVP composite. This technique leads to the formation of broad bean‐shaped WSe 2 nanoflakes, which are evenly combined with a PVP polymer, resulting in an enlarged nanoflakes electrode material coated with Ni foam. Also, the WSe 2 @PVP composite, when tested as an electrode in a 2 M KOH electrolyte, achieves a Cs of 393.1 F g −1 at a current density of 1 A g −1 . This was significantly more than the capacitance of the bare WSe 2 electrode, which demonstrated a Cs of 233.3 F g −1 at a current density of 1 A g −1 . Furthermore, the composite showed excellent rate capability and impressive cyclic stability, retaining 98% of its initial capacitance after 5000 cycles. The larger surface area for reactions, faster electron and ion transport routes, improved electroactive sites, and, most importantly, effective electrolyte penetration into the composite structure are the major reasons for WSe 2 @PVP improved electrochemical performance.