Dielectrophoretic Assembly of Silver Nanowires for Surface-Area-Enhanced Micro-Supercapacitors

Micro-supercapacitors (MSCs) have emerged as strong candidates for on-chip and miniaturized energy storage, offering rapid charge–discharge behavior and long-term cycling stability that conventional batteries cannot match. Their practical deployment, however, is limited by comparatively low energy density, a shortcoming rooted largely in the restricted active surface area of planar electrode geometries. This work presents a dielectrophoresis (DEP)-assisted assembly route that overcomes this constraint by extending the electrode architecture into three dimensions. When a silver nanowire (AgNW) suspension is exposed to an alternating electric field, individual nanowires migrate toward regions of high field gradient at the electrode edges, align along the field direction, and progressively chain together into microwires that bridge the interdigitated electrode fingers. The resulting self-assembled network is subsequently coated with a conformal gold layer, which suppresses chemical degradation of the underlying silver while ensuring low-resistance electrical continuity across the wire–electrode junctions. Compared with reference devices fabricated without nanowire incorporation, the hybrid electrode network delivers an approximately 33% increase in effective surface area, which translates into a specific capacitance enhancement of up to 93%. These results demonstrate that field-directed nanowire assembly is an effective and scalable strategy for improving MSC performance, advancing their viability as reliable power sources for compact electronic systems.