A system for performing simultaneous in situ atomic force microscopy/optical microscopy measurements on electrode materials for lithium-ion batteries

An atomic force microscope (AFM) equipped with an optical charge coupled de vice camera has been placed in an Ar filled glovebox for the purpose of stu dying the change in morphology of electrode materials as they react with li thium. In order to minimize noise induced by vibration, the AFM is mounted on granite blocks suspended from the ceiling of the glovebox by a combinati on of flexible rubber cords and metal springs. The AFM, which is equipped w ith an environmental chamber surrounding the sample, is then enclosed in a specially constructed draft shield that allows the circulation of Ar gas by the purification system during imaging. A special electrochemical cell was constructed to hold the working electrode under study. Repeated imaging wi th little drift is possible while electrodes are reacted with lithium for p eriods of many days. Examples of measurements made by this device will be g iven for the case of lithium alloying with sputter-deposited Si-Sn thin fil ms. The optical and AFM images obtained as a function of lithium content in the films are assembled into time-lapsed "movies" showing the evolution of the morphology of the sample along with the corresponding electrochemistry . These movies are available for download through the Electronic Physics Au xiliary Publication Service (EPAPS). (C) 2001 American Institute of Physics .