Controlled synthesis of high-yield, high-tapped-density spherical silver powder for wearable strain sensing

Monodisperse microspherical silver powder with a high yield of 99.9%, high tapped density, and excellent dispersibility was prepared via a controlled liquid-phase reduction route. • Ag(111)-based simulations revealed dispersant adsorption behavior, while experiments confirmed their regulation of silver particle growth. • The prepared silver powder was further used to construct a flexible wearable sensing materials, enabling real-time monitoring of various human motions. High-quality monodisperse microspherical silver powders hold considerable promise for conductive pastes and flexible electronics. However, the concurrent realization of high yield, dense packing, and excellent dispersibility remains challenging. Herein, we report a controlled liquid-phase reduction route based on an ammoniacal silver complex, using formaldehyde as reductant and stearic acid as dispersant. The resulting silver powder exhibits an ultrahigh yield of 99.9%, a tapped density of 6.0 g/cm 3 , and excellent sphericity and dispersibility. Moreover, this exceptional performance is enabled by a stable organic interfacial layer formed through carboxyl-group adsorption on the silver surface, which suppresses disordered agglomeration and promotes uniform particle growth. Notably, a flexible strain sensor constructed from this powder delivers a rapid response time of 125 ms and stable real-time monitoring of various human motions. This work demonstrates a practical pathway for the controlled synthesis of high-performance spherical silver powder for wearable sensing applications.