News & Newsletters

A New Tool For Mapping The NanoElectrochemical Characteristics of Battery Interfaces: AFM SECM

An Exemplary Publication By A Nanonics Customer: Kiran Mahankali, Naresh Kumar Thangavel, and Leela Mohana Reddy Arava, “In Situ Electrochemical Mapping of Lithium–Sulfur Battery Interfaces Using AFM–SECM,” Nano Lett. 2019, 19, 8, 5229–5236 https://doi.org/10.1021/acs.nanolett.9b01636

Lithium based batteries drive many of the electronics that we use in our daily lives. Significant interest has developed on a variant known as lithium-sulfur (Li-S) batteries. These batteries could result in a significant advance in achieving more power with lighter and smaller packaging. However, several challenges lie ahead for their development. These mainly are related to the electrochemical processes that underlie the function of these batteries and result in the irreversible deposition of insulating materials that perturb battery function.

Scanning electrochemical microscopy (SECM) is a powerful method to look at local electrochemical changes and can even image the nature of these changes. Thus, its application has great potential to affect new understandings that could lead to improvements in such battery function.

SECM has generally used straight glass probes filled with metal as an electrode to image electrochemical reactions occurring on surfaces. It is recognized that such glass probes are ideal for electrochemical imaging. However, these probes have lacked the important ability to integrate AFM topography. Without such imaging SECM has lacked the ability to separate morphology from electrochemical activity and also the lack of AFM feedback has restricted SECM imaging with probes that are less than several microns. The group of Reddy Arava at Wayne State University has applied the developments of Nanonics to combine the excellence of glass SECM probes with AFM. This integration of simultaneous AFM-SECM measurements does not obstruct the optical axis therefore permitting SECM, topography and spectroscopic techniques such as Raman on-line imaging. Furthermore, Nanonics integration of tuning fork for AFM/SECM feedback allows Raman imaging without any optical background. This synergistic integration was highlighted by Arava et al in their research focus on battery electrochemical fundamentals. Specifically, their NanoLetters paper shows :

• AFM imaging allows tracking the dynamic dissolution and precipitation of active sulfur species.
• AFM-SECM allows distinguishing between chemical and electrochemical surface reactions.

To summarize this paper highlights the importance of such a combination of techniques to offer new insights into next generation Li-S batteries.

The authors have been able to show that the SECM/AFM/Raman can map effectively the deposition on a nanoscale of conductive and non-conductive materials and thus better understand Li-S battery charging and recharging mechanisms and battery failure.

Learn More About Integrated AFM Electrochemical & Raman Imaging

A new tool for investigating Nanophotonics Devices-FNTM 

Recent Advance By Nanonics Customer: Seo, E., Jin, Y., Choi, W. et al. Near-field transmission matrix microscopy for mapping high-order eigenmodes of subwavelength nanostructures. Nat Commun 11, 2575 (2020). https://doi.org/10.1038/s41467-020-16263-z

The amplitude and phase of higher order eigenmodes in interacting optical nanostructures has been imaged with 50nm resolution using a 150nm near-field scanning optical microscope (NSOM) collection mode aperture.

 The group at Korea University and Samsung Advanced Institute of Technology combined a Nanonics MultiView 2000 system with a spatial light modulator and nanometric collection of light without any optical background. This has allowed:

• Visualization of the formation and coupling of the fundamental optical modes of the interacting nanophotonic system
• Coupling these modes with the other spatially and spectrally overlapped modes
• Reaching a resolution that was 1/3 the diameter of the near-field optical imaging aperture of 150nm.

Why is that Important?

The techniques developed in this publication will have important implications as optical nanostructures are designed to achieve greater density for merging multiple functionalities on one chip.  The methodologies will address the challenges ahead in engineering the hybridized modes having distinct resonances with minimal cross-talk.

This addition to conventional NSOM addresses the issues of multiple near-field optical eigenmodes and the part they play in the functionalization of optical devices based on interacting optical structures. Inevitably, these eigenmodes are highly multiplexed in their spectra and superposed in their spatial distributions. 

The elegant application of the optical polarization of the Nanonics’ optical fiber probe with the flexibility and free optical axis of the sample and probe scanners in the Nanonics MV2000 extends nano-optical measurement technology to enable :

• Mapping out higher orders of individual eigenmodes of structures interacting on a scale of <150nm.
• Allowing the extraction of orthogonal near-field eigenmodes such as anti-symmetric and quadruple modes of multiple optical nanostructures that are smaller than the probe aperture dimension.
• Permitting the separate mapping of multiple hybridized and superposed eigenmodes that are formed by the coupling between the modes of the constituent nanostructures.
• Constructing a fully phase-referenced far- to near-field transmission matrix (FNTM), which describes the far-field input to near-field output response of the given nanostructures and visualize the antisymmetric mode, quadruple mode, and other high-order modes which were completely hidden under the conventional NSOM images, and to quantify their relative coupling efficiency from their eigenvalues.         

Ultra Sensitivity of Tuning Forks in Photon Force Imaging (PiFM)

Recent Advance By Nanonics Customer: Jahng et al “Photo-Induced Force Microscopy by Using Quartz Tuning-Fork Sensor” Sensors 2019, 19, 1530; doi:10.3390/s19071530

MultiView2000

Probe Mounted on Tuning Fork

MultiView 4000 MultiProbe