The electrode/electrolyte interface plays a cri- tical role in the performance of a Li-ion battery. In view of the dynamic and complex nature of the interface, in situ research approaches can provide valuable information of interfacial phenomena during battery operation. In situ scanning probe microscopy （SPM） is a powerful technique used for the interfacial investigation of the Li-ion batteries. The versatile SPM techniques and their various operation modes have been utilized to measure the morphology and other properties of the electrode interface at high resolu- tion. Herein, we discuss the related SPM techniques to study the topography, mechanics and electrochemistry re- search of electrodes. Recent progresses of in situ SPM research on the electrode/electrolyte interface are summa- rized. Finally, the outlook of the technique is discussed.
Tip-enhanced Raman spectrum(TERS) is a scanning probe technique for acquiring chemical information at high spatial resolution and with high chemical sensitivity. The sensitivity of TERS with atomic force microscopy(AFM) system is mainly determined by the metalized tips. Here, we report a fabrication protocol for AFM-TERS tips that incorporate a copper(Cu) primer film between a gold(Au) layer and a Si AFM tip. They were fabricated by coating the Si tip with a 2 nm Cu layer prior to adding a 20 nm Au layer. For top illumination TERS experiments, these tips exhibited superior TERS performance relative to that observed for tips coated with Au only. Samples included graphene, thiophenol and brilliant cresyl blue. The results may derive from the surface roughness of the tip apex and a Cu/Au synergism of local surface plasmon resonances.
We investigated the interfacial electrochemical processes on graphite anode of lithium ion battery by using highly oriented pyrolytic graphite(HOPG)as a model system.In situ electrochemical atomic force microscopy experiments were performed in 1M lithium bis(trifluoromethanesulfonyl)imide/ethylene carbonate/diethyl carbonate to reveal the formation process of solid electrolyte interphase(SEI)on HOPG basal plane during potential variation.At 1.45 V,the initial deposition of SEI began at the defects of HOPG surface.After that,direct solvent decomposition took place at about 1.3 V,and the whole surface was covered with SEI.The thickness of SEI was 10.4±0.2 nm after one cycle,and increased to 13.8±0.2 nm in the second cycle,which is due to the insufficient electron blocking ability of the surface film.The Young’s modulus of SEI was measured by a peak force quantitative nanomechanical mapping(QNM).The Young’s modulus of SEI is inhomogeneous.The statistic value is 45±22 MPa,which is in agreement with the organic property of SEI on basal plane of HOPG.
