Jingshan S. Du, Jungwon Park, QHwan Kim, Wonho Jhe, Vinayak P. Dravid, Deren Yang, David A. Weitz
Solid-state transformation between diff erent materials is often accompanied
by mechanical expansion and compression due to their volume change and
structural evolution at interfaces. However, these two types of dynamics are usually
diffi cult to monitor in the same time. In this work, we use in situ transmission electron
microscopy to directly study the reduction transformation at the AgCl− Ag interface.
Three stages of lattice fl uctuations were identifi ed and correlated to the structural
evolution. During the steady state, a quasi-layered growth mode of Ag in both vertical and
lateral directions were observed due to the confi nement of AgCl lattices. The development
of planar defects and depletion of AgCl are respectively associated with lattice
compression and relaxation. Topography and structure of decomposing AgCl was further
monitored by in situ scanning transmission electron microscopy. Silver species are
suggested to originate from both the surface and the interior of AgCl, and be transported
to the interface. Such mass transport may have enabled the steady state and lattice
compression in this volume-shrinking transformation.