# Designing TEM experiments with thin lamella all-solid-state cells in controlled atmosphere using electrochemical chips

Paul Naillou, Adrien Boulineau, Sami Oukassi, Philippe Azaïs

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Paul Naillou, Adrien Boulineau, Sami Oukassi, Philippe Azaïs. Designing TEM experiments with thin lamella all-solid-state cells in controlled atmosphere using electrochemical chips. Micron, 2025, 192-193, pp.103810. 10.1016/j.micron.2025.103810. hal-05350985

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# Designing TEM experiments with thin lamella all-solid-state cells in controlled atmosphere using electrochemical chips

Paul Naillou<sup>a,*</sup> <sup>●</sup>, Adrien Boulineau<sup>a</sup>, Sami Oukassi<sup>b</sup>, Philippe Azaïs<sup>a</sup>

<figure><img src="image_3.png" /></figure>

## ARTICLE INFO

**Keywords:**

Lithium-ion

All-solid-state

TEM

Operando

E-chip

## ABSTRACT

While *in situ* techniques in transmission electron microscopy (TEM) field provide increasingly more useful and accurate data on various physical phenomena, electrochemical reactions occurring on interfaces in all-solid-state lithium-ion batteries (ASSLIB) still remain incompletely understood. High resolution and time-resolved TEM observations of interfaces stand as the pinnacle of battery research, but current most promising solid electrolyte materials exhibit major inconveniences for standard characterization protocols such as ambient air sensitivity. While several groups have developed methods to study lithium-ion cells in *in situ* TEM, mostly through thin lamella preparation, few seemed to have kept the sample in controlled atmosphere. Yet, this can stand as a critical criterion for maintaining material integrity during transfer and acquisition. In this work, we describe our attempt to lead *operando*-TEM characterization on a thin lamella all-solid-state lithium-ion cell by a new technique involving the use of a specific controlled-atmosphere sample holder and electrochemical chips including electron-transparent windows. Achievements, challenges and prospects of this method are discussed here.

## 1. Introduction

Liquid electrolytes imply the presence of liquid-solid interfaces and are difficult to study through TEM due to electron beam behaviour in liquids such as multiple scattering, radiolysis and bubble formation (Schneider et al., 2014; Kashin and Ananikov, 2019; Grogan et al., 2014). All-solid-state Lithium-ion cells (ASSLIB) only contain solid-solid interfaces, enabling multiple possibilities of characterization techniques. Moreover, interfacial phenomena in ASSLIB are poorly understood and remain as the main drawback for their implementation in modern devices (Lim et al., 2020; Banerjee et al., 2020). ASSLIB notably suffer from a drastic loss of capacity and increase of impedance during the first cycles due to the formation of resistive cathode-electrolyte interfaces (Kato et al., 2016). Efforts have been led to unveil the chemical composition and the mechanisms involved in the formation of those interfaces, but the limited ability of simple *ex situ* observations to provide a satisfying understanding of the interfacial stability has encouraged the research community to look for novel characterization methods. On this occasion, several groups have been using focused ion-beam (FIB) milling in order to prepare thin lamella containing full or half cells with a thickness down to ~80 nm (Brazier et al., 2008; Wang

et al., 2016; Gong et al., 2018; Gong et al., 2017; Hammad Fawey et al., 2016), thin enough to enable high resolution imaging and to perform TEM-related techniques such as electron energy-loss spectroscopy (EELS) and selected area electron diffraction (SAED). Those techniques provide information on chemical environment of materials, crystallographic structure and lithium diffusion dynamics. This approach is encountered for the first time with *post-mortem* studies of such nanobatteries by Brazier et al. (Brazier et al., 2008) calling for later *in situ* studies in which TEM observations are performed while applying cycling conditions (Wang et al., 2016; Gong et al., 2018; Gong et al., 2017; Hammad Fawey et al., 2016; Nomura et al., 2018). The challenges identified through this concept are mainly about being able of: (i) milling a lamella containing electrodes, electrolyte and collectors and (ii) closing the system into a functional electrochemical device. While the first relies on the choice of a source stack of materials and a careful thinning process, several solutions have been proposed to solve the second concern. Successful experiments have been conducted using a STM tip introduced inside the TEM chamber to close the circuit with the support grid as opposite electrode (Wang et al., 2016) while other groups deposited a lamella between the contacts of an electrochemical chip (Gong et al., 2018; Gong et al., 2017; Hammad Fawey et al., 2016),

<footnote><sup>a</sup> Université Grenoble Alpes, CEA, LITEN, Grenoble 38000, France</footnote>

<footnote><sup>b</sup> Université Grenoble Alpes, CEA, LETI, Grenoble 38000, France</footnote>

<footnote>* Corresponding author.</footnote>

<footnote>E-mail address: naillou@ill.fr (P. Naillou).</footnote>
<figure><img src="image_4.png" /><figcaption>**Fig. 1.** (a–b) Protochips Poseidon Select holder illustrations from supplier; (c) top chip; (d) bottom chip; (e–j) sample installation steps: the components of the tip are successively installed inside the glovebox, guaranteeing the conservation of an inert atmosphere.</figcaption></figure>

allowing a wider range of motion inside the chamber and procedures such as zone-axis alignments. Therefore, each of those experiments imply the use of a free-standing lamella, which exposes the materials to ambient atmosphere during transfer. Here, a new approach is introduced using a TEM sample holder providing an environment closed by

two stacked microchips including each an electron-transparent SiN window aligned with the optical axis. The microchips are separated by a 1 µm-thick continuous spacer, enabling to keep a constant atmosphere from when the device is mounted, which is realized in Ar-filled glovebox. The top microchip includes electrical tracks connected to the
<figure><img src="image_5.png" /><figcaption>**Fig. 2.** General scheme of a thin ASSLIB lamella preparation, transfer and operando-TEM characterization. A stack of cell components is extracted as a thin lamella in a FIB-SEM microscope and deposited over a microchip transparent SiN window using a specific procedure. The microchip is transferred from the FIB to the glovebox using a shuttle and mounted inside the Poseidon Select TEM sample holder. The microchip is protected from the environment by SiN electron-transparent windows and a static spacer. TEM imaging and related analyses (EDX, EELS, SAED) can be performed under various electrochemical conditions.</figcaption></figure>
<table><caption>**Table 1**
FIB procedure of lamella extraction.</caption><thead><tr><th>Step</th><th>Description</th><th>Stage tilt<sup>a</sup></th><th>Stage rotation</th><th>Current</th></tr></thead><tbody><tr><td>1a</td><td>Search and select a 3 × 15 µm region of interest</td><td>0°</td><td>0°</td><td></td></tr><tr><td>1b</td><td>Mill the protection layer over the surface</td><td>0°</td><td>0°</td><td>100 pA</td></tr><tr><td>1c</td><td>IBID deposition of 1 µm-thick Pt protection layer</td><td>54°</td><td>0°</td><td>700 pA</td></tr><tr><td>1d</td><td>Mill 10 µm-deep trapezes around the sample</td><td>54°</td><td>0°</td><td>30 nA</td></tr><tr><td>1e</td><td>Rough thinning of the lamella to ~1 µm</td><td>54°</td><td>0°</td><td>1.5 nA</td></tr><tr><td>1f</td><td>« U-milling » around the lamella, leaving a small bridge</td><td>9°</td><td>0°</td><td>1.5 nA</td></tr><tr><td>1g</td><td>Bring the micromanipulator</td><td>54°</td><td>0°</td><td></td></tr><tr><td>1h</td><td>Weld the micromanipulator to the edge of the lamella</td><td>54°</td><td>0°</td><td>20 pA</td></tr><tr><td>1i</td><td>Mill the bridge</td><td>54°</td><td>0°</td><td>700 pA</td></tr><tr><td>1j</td><td>Extract the lamella and retract the micromanipulator</td><td>54°</td><td>0°</td><td></td></tr></tbody></table>

sample holder toward a potentiostatic setup outside the microscope. This design allows a large range of motion inside the chamber and prevents any degradation of the materials to occur because of the ambient air exposure, which stands as a game changer for sulfide electrolytes studies for instance. Some phase transformations are also the sources of large volume changes in electrode materials, implying a loss of contact with the solid electrolyte in actual batteries (Koerver et al., 2017) and might generate mechanical strains in a free-standing lamella leading to its collapse. The use of a supporting window helps to keep the integrity of the lamella and to perform characterizations, even after a change of volume, a contact loss or a large interphase formation.

## 2. Experimental

### 2.1. Equipment

Scanning transmission electron microscopy (STEM) imaging and energy dispersive X-ray spectroscopy (EDX) have been led with FEI Tecnai Osiris TEM equipped with Super-X EDX detector and operated at 200 kV. The specific sample holder used in this work is a Protochips

Poseidon Select, diverted from its initial purpose on liquid samples characterization in order to maintain controlled atmosphere. Microchips are provided by Protochips and fit with the Poseidon Select holder. Thin film micro-batteries have been supplied by CEA Leti (Cele et al., 2023) to facilitate FIB extraction of a cathode-electrolyte-anode stack with dimensions suitable for the fabrication of TEM lamella. LiCoO₂, LiPON, and Ti films have been sequentially deposited on 8-inch silicon substrates via reactive sputtering, followed by patterning using standard microfabrication techniques (Oukassi et al., 2019). Focused ion-beam & scanning electron microscopy (FIB-SEM) operations have been led with a modified Zeiss 550 microscope.

The details of the TEM sample holder setup are presented in Fig. 1. The tip of the holder contains a stack of a joint, a bottom chip including a spacer, a top chip including electrical connections and a cap, maintained enclosed with three screws. The SiN window of the top chip is around 60 × 120 µm and 20 nm-thick while the bottom chip has a wide and ~120 µm tall window. Therefore, the chips have to be carefully aligned together during the sample holder installation, described in Fig. 1e-j. This procedure can be followed in ambient air or in Ar-filled glovebox for sensitive samples after a protected transfer from FIB microscope. For a better understanding of the general concept, a scheme is presented in Fig. 2 summarizing each main step, namely (i) FIB fabrication of the cell-containing microchip device, (ii) microchip installation in sample holder and transfer and (iii) STEM characterization of the sample.

### 2.2. FIB procedure

Usual FIB lamella fabrication consist of the extraction of a thin lamella from bulk material and of its free-standing deposition on the edge of a TEM support. Despite the extraction and thinning steps are standard here, the flat deposition of the lamella upon the SiN window and the geometrical constraints associated require a specific procedure. Additional features are also necessary, such as collectors and tracks in order to electrically close the system; their fabrication is described here.

The first main step is the lamella extraction of which the procedure is described as substeps in Table 1 and is illustrated in Fig. 3. The sample is a stack of different layers, from top to bottom: Ti-based anode, LiPON electrolyte, LiCoO₂ (LCO) cathode. By milling at a 10 µm depth, all of the components can be included in one lamella. LiPON/LCO interface

<figure><img src="image_6.png" /><figcaption>**Fig. 3.** FIB-SEM images of lamella extraction indexed in reference to Table 1. The Pt protection is deposited over the surface to protect the top layer from beam damage and will be used as a current collector for the device at the same time. Pools and a U-cut are coarsely milled around the lamella, which will be welded to the micromanipulator using IBID. The micromanipulator is released by finishing the cut on the side of the lamella.</figcaption></figure>

<footnote>a Stub plan is horizontal, stub reference is identical to stage reference</footnote>
<table><caption>**Table 2**
FIB procedure of lamella deposition.</caption><thead><tr><th>Step</th><th>Description</th><th>Stage tilt<sup>b</sup></th><th>Stage rotation</th><th>Current</th></tr></thead><tbody><tr><td>2a</td><td>Weld lamella on the edge of microchip</td><td>0°</td><td>0°</td><td>20 pA</td></tr><tr><td>2b</td><td>Mill and retract the micromanipulator</td><td>0°</td><td>0°</td><td>700 pA</td></tr><tr><td>2c</td><td>Progressive lamella thinning, starting at 700 pA</td><td>0°</td><td>0°</td><td>100 pA</td></tr><tr><td>2d</td><td>Tilt and weld the micromanipulator to the lamella</td><td>36°</td><td>0°</td><td>20 pA</td></tr><tr><td>2e</td><td>Extract the lamella</td><td>36°</td><td>0°</td><td>700 pA</td></tr><tr><td>2f</td><td>Approach of the lamella to the surface of SiN window</td><td>45°</td><td>180°</td><td></td></tr><tr><td>2g</td><td>Low current weld of the Pt-protection edge of the lamella directly on the window</td><td>45°</td><td>180°</td><td>20 pA</td></tr><tr><td>2h</td><td>Low current mill and retract the micromanipulator</td><td>45°</td><td>180°</td><td>20 pA</td></tr><tr><td>2i</td><td>IBID deposition of Pt collector on edge of the cathode</td><td>9°</td><td>0°</td><td>50 pA</td></tr><tr><td>2j</td><td>IBID deposition of Pt tracks between collectors and microchip electrodes</td><td>9°</td><td>0°</td><td>20 pA</td></tr></tbody></table>

has been already studied in such *operando* experiments (Wang et al., 2016) and proved its easy handling, particularly regarding lamella fabrication and thinning. A first layer of Pt is added above by ion beam-induced deposition (Wang et al., 2016) and will be used as a ion beam protection during further milling steps as well as a conductive layer for current collection. The lamella is extracted at 54°, and is able this way to be flipped during the second main step, that is flat deposition of the lamella. In this aim, the blank microchip is tied with claws upon a 45° inclined stub. Substeps of lamella deposition are described in Table 2 and illustrated in Fig. 4. We should notice that the parallelism of the lamella during its thinning process is critical in order to obtain a flat deposition, avoiding any extra space between the opposite edge of the lamella, regarding the micromanipulator attach, and the SiN window. After the lamella is welded to the window, Pt cathodic collector and tracks toward the microchip electrodes are carefully deposited using (Wang et al., 2016) at low current to preserve the integrity of fragile SiN window.

## 2.3. Transfer from FIB

In order to keep the sample in controlled atmosphere, a sample transfer shuttle (Zeiss) is used (cf. Fig. S1a). The stub carrying the microchip is mounted on the sample holder (cf. Fig. S1b), which is inserted in the shuttle, all inside the glovebox. The shuttle can be closed remotely via an infrared remote control, hence locked in with inert atmosphere. The vessel is transferred to the FIB and opened remotely in the airlock while pumping to vacuum. The sample holder can be detached from the shuttle, staying in the airlock area and pushed to the sample position in the chamber using the compatible transfer rod of the Zeiss microscope. When the FIB procedure is finished, the sample holder is brought back to the shuttle and remotely closed before opening the airlock to ambient air. The vessel keeps a low vacuum atmosphere until it is transferred to the glovebox, where it is opened to transfer the microchip to the TEM sample holder. A valve is present on the shuttle to let enter external atmosphere when the difference of pressure is too high for the motors. No increase of the O₂ and H₂O contents is remarked during the opening, staying below 1 ppm and confirming the good functioning of the device.

## 3. Results & discussion

Using the procedure described in the experimental section of this work, several lamellae have been successfully transferred from a bulk sample to microchips and then characterized in a TEM. But despite the apparent integrity of the device, their ability to cycle has shown to be

dependant of several crucial experimental parameters. Far from trivial, several challenges have been encountered during the deposition of the lamellae or the Pt tracks on the SiN window. Those potential issues are discussed section hereinafter. FIB-SEM and STEM-HAADF images illustrating those situations are provided in Supplementary Information (Fig. S2).

* The SiN window is 20 nm-thick and very fragile: high IBID current (> 20 pA), careless micromanipulator milling, slight angle of the lamella with the window or unexpected movement of the lamella due to electrostatic forces approaching the window can result into its breaking. Breakage of the window can also occur during the transfer to TEM (cf. Fig. S2a-b).

* When the thinning is not perfectly parallel, when the lamella moves due to electrostatic forces or if any constrain occurs during micromanipulator use resulting in some wrong angle, the lamella cannot be deposited perfectly flat. This results into an empty space between an edge of the lamella and the window, therefore the Pt bridge deposited to connect the lamella to the Pt tracks must be significantly thick and implies a strong Pt contamination over the sample (cf. Fig. S2c).

* When disengaging the micromanipulator from the deposited lamella at step 2 h, the tip should be milled carefully in order to avoid any Pt contamination behind the bridge, which could result into a short-circuit (cf. Fig. S2d). Milling in the opposite direction bypasses this issue but a low current should be used to avoid the breakage of the window behind.

* The most restrictive consequence to prevent is the global Pt contamination induced by electron or ion imaging after IBID. The Pt precursor in the FIB-SEM chamber is not completely evacuated after each IBID step and the remaining compound is cracked over the surface while imaging the surface. The recommendations to avoid this situation is to not perform electron imaging during IBID and to wait for the precursor evacuation before continuing the procedure, but despite the strict application of this protocol, a clearly visible contamination is encountered. Bright areas are observed by SEM imaging on the surface of the SiN window (visible in Figs. 4 and 5, indicated on Fig. S2f), corresponding to Pt electron beam induced deposition from imaging.

In the latest design, Pt tracks are deposited before the lamella following the configuration shown in Fig. 5. This way, (Wang et al., 2016) contaminations around each electrode track are not overlapping and not covering the surface of the lamella. But this design still suffers from short-circuits identified by open circuit voltage measurements. The lamella obtained with this experimental procedure and cautious Pt deposition conditions has been characterized by EDX, spectra are presented in Fig. 5 and show a very high Pt content. A reference EDX acquisition of a similar free-standing lamella studied from a copper support is plotted over this acquisition, highlighting the abnormal amount of Pt detected. Pt contamination has been already reported as a major concern in such electrochemical devices (Hammad Fawey et al., 2016) Some solutions have been proposed for this issue concerning free-standing lamellae, like building Pt protection walls around the lamella before thinning it to remove contamination but the fragility of the SiN window prevents from any cleaning procedure after the lamella is deposited on its surface. Low current grazing ion beam has shown to be destructive enough to damage the window through this study. Also, the 1 µm spacer of the bottom microchip does not allow to use any higher feature over the window. The smallest spacer is aimed in the end to minimize beam broadening and a decrease of spatial resolution. Spacers going down to 100 nm are available, however this implies a careful thinning process, a strictly parallel approach of the lamella toward the window and the deposit of thin bridges of Pt. Moreover, the absence of β-tilt for the Poseidon Select sample holder complicates the alignment of materials in zone axis, while the α-tilt range is ± 37°. High

<footnote><sup>b</sup> Stub plan is inclined at 45°, angles are indicated at stage reference</footnote>
<figure><img src="image_7.png" /></figure>

<figure><img src="image_8.png" /></figure>

<figure><img src="image_9.png" /></figure>

<figure><img src="image_10.png" /></figure>

<figure><img src="image_11.png" /></figure>

<figure><img src="image_12.png" /></figure>

<figure><img src="image_13.png" /></figure>

2a lamella deposition on microchip edge

2e lame la extraction with 36° angle

2g flat deposition of lamella on microchip

2i/2j Pt tracks & collectors deposition

<figure><img src="image_14.png" /></figure>

<figure><img src="image_15.png" /></figure>

<figure><img src="image_16.png" /></figure>

* items not to scale

2c lamella thinning

<figure><img src="image_17.png" /></figure>

<figure><img src="image_18.png" /></figure>

<figure><img src="image_19.png" /></figure>

<figure><img src="image_20.png" /></figure>

<figure><img src="image_21.png" /></figure>

<figure><img src="image_22.png" /><figcaption>**Fig. 4.** Schemes and FIB-SEM images of lamella deposition indexed in reference to Table 2. The lamella was extracted at 54° angle in the previous protocol, hence a first step consists in depositing the lamella on the side of the microchip to retrieve a flat orientation. Then, the horizontal lamella is carefully deposited over the window of the microchip. The Pt protection is welded to the window using IBID to connect the lamella to the microchip before releasing the micromanipulator.</figcaption></figure>
<figure><img src="image_23.png" /><figcaption>**Fig. 5.** Study of a LiPON/LCO lamella cell deposited over the SiN window of the microchip. SEM images have been acquired in FIB-SEM during fabrication while STEM-HAADF images and EDX acquisitions have been acquired in TEM after transfer. EDX maps of the full lamella and the LiPON/LCO interface are shown. EDX spectra for LCO and LiPON regions of this lamella (solid line) are plotted with reference EDX spectra for same regions of a free-standing lamella studied from a standard copper grid (dotted line).</figcaption></figure>
<figure><img src="image_24.png" /><figcaption>**Fig. 6.** Swelling of LiPON electrolyte in an *operando* device short-circuited with IBID Pt after applying a 3 V voltage.</figcaption></figure>

resolution in STEM acquisition mode still remains somehow challenging, but not inconceivable. Columnar LCO cathode such as presented in Fig. 5 are a typical example of materials that increase the probability to find a zone axis without β-tilt due to their intrinsic orientation in the layer stack.

The most visible consequence of the short-circuit induced by Pt contamination in the lamella cell is the swelling of the electrolyte while applying a voltage. The heating of the electrolyte results into a fully destructive transformation shown in Fig. 6. In spite of the statement of failure of this cell, the lamella is still cohesive and maintained at the same spot thanks to the supporting window. This demonstrates the ability of the design to lead a large variety of investigations on cells, including highly destructive transformations.

Regarding the current issues of Pt contamination, efforts must be pursued to perform electrochemical cycling and time-resolved TEM acquisitions on this device. Nonetheless, the design proposed in this work should open prospects for many solid electrolyte materials showing immediate degradation through ambient air exposure and for the study of phase transformations with changes of volume. Those experiments have raised the interest of using microchips with SiN windows for cell characterization, showing the feasibility of some concerning steps such as flat deposition of the lamella. Despite the contamination, Pt tracks have been also successfully deposited on the window, pointing out that a very low current has to be used in this procedure (≤ 20 pA). We propose that further experiments include FIB-prepared stencil masks to print Pt connections and cathodic current collector without contaminating surrounding materials.

## 4. Conclusion

This work has shown how a thin lamella fabricated by FIB-milling and comprising a full cell composition can be deposited on an electrochemical microchip and transferred to a TEM. This device is a close system kept in a controlled atmosphere and the window acts as a supportive and inert layer for the lamella cell. Nonetheless, Pt contamination during (Hammad Fawey et al., 2016) of tracks and collector leads to unavoidable short-circuits. Despite the design has to be improved to perform time-resolved *operando*-TEM experiment, such approach offers the perspective of unparalleled experiments especially considering the promising cells based on sulfide compounds.

## Funding

This work, carried out on the Platform for Nanocharacterisation (PFNC), was supported by the "Recherche Technologique de Base" and "France 2030 - ANR-22-PEEL-0014" programs of the French National Research Agency (ANR).

## CRediT authorship contribution statement

**Naillou Paul:** Writing – original draft, Methodology, Investigation, Formal analysis. **Oukassi Sami:** Writing – review & editing, Validation, Resources. **Boulineau Adrien:** Writing – review & editing, Validation, Supervision, Resources, Project administration, Methodology,

Conceptualization. **Azaïs Philippe:** Writing – review & editing, Supervision, Resources, Project administration.

## Declaration of Competing Interest

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Paul Naillou reports financial support was provided by French National Research Agency. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

## Appendix A. Supporting information

Supplementary data associated with this article can be found in the online version at doi:10.1016/j.micron.2025.103810.

## Appendix B. Supporting information

Supplementary data associated with this article can be found in the online version at doi:10.1016/j.micron.2025.103810.

## Data availability

The data that has been used is confidential.

## References

* Banerjee, A., Wang, X., Fang, C., Wu, E.A., Meng, Y.S., 2020. Interfaces and interphases in all-solid-state batteries with inorganic solid electrolytes. Chem. Rev. 120 (14), 6878-6933. https://doi.org/10.1021/acs.chemrev.0c00101.

* Brazier, A., Dupont, L., Dantras-Laffont, L., Kuwata, N., Kawamura, J., Tarascon, J.-M., 2008. First cross-section observation of an all solid-state lithium-ion "nanobattery" by transmission electron microscopy. Chem. Mater. 20 (6), 2352-2359. https://doi.org/10.1021/cm7033933.

* Celé, J., Franger, S., Lamy, Y., Oukassi, S., 2023. Minimal architecture lithium batteries: toward high energy density storage solutions. Small 19 (16), 2207657. https://doi.org/10.1002/smll.202207657.

* Gong, Y., Zhang, J., Jiang, L., Shi, J.-A., Zhang, Q., Yang, Z., Zou, D., Wang, J., Yu, X., Xiao, R., Hu, Y.-S., Gu, L., Li, H., Chen, L., 2017. In situ atomic-scale observation of electrochemical delithiation induced structure evolution of LiCoO₂ cathode in a working all-solid-state battery. J. Am. Chem. Soc. 139 (12), 4274-4277. https://doi.org/10.1021/jacs.6b13344.

* Gong, Y., Chen, Y., Zhang, Q., Meng, F., Shi, J.-A., Liu, X., Liu, X., Zhang, J., Wang, H., Wang, J., Yu, Q., Zhang, Z., Xu, Q., Xiao, R., Hu, Y.-S., Gu, L., Li, H., Huang, X., Chen, L., 2018. Three-dimensional atomic-scale observation of structural evolution of cathode material in a working all-solid-state battery. Nat. Commun. 9 (1), 3341. https://doi.org/10.1038/s41467-018-05833-x.

* Grogan, J.M., Schneider, N.M., Ross, F.M., Bau, H.H., 2014. Bubble and pattern formation in liquid induced by an electron beam. Nano Lett. 14 (1), 359-364. https://doi.org/10.1021/nl404169a.

* Hammad Fawey, M., Chakravadhanula, V.S.K., Reddy, M.A., Rongeat, C., Scherer, T., Hahn, H., Fichtner, M., Kübel, C., 2016. In situ TEM studies of micron-sized all-solid-state fluoride ion batteries: preparation, prospects, and challenges: micron-sized all-solid-state fluoride ion batteries. Microsc. Res. Tech. 79 (7), 615-624. https://doi.org/10.1002/jemt.22675.

* Kashin, A.S., Ananikov, V.P., 2019. Monitoring chemical reactions in liquid media using electron microscopy. Nat. Rev. Chem. 3 (11), 624-637. https://doi.org/10.1038/s41570-019-0133-z.

* Kato, Y., Hori, S., Saito, T., Suzuki, K., Hirayama, M., Mitsui, A., Yonemura, M., Iba, H., Kanno, R., 2016. High-power all-solid-state batteries using sulfide superionic conductors. Nat. Energy 1 (4), 16030. https://doi.org/10.1038/nenergy.2016.30.

* Koerver, R., Dursun, I., Leichtweiß, T., Dietrich, C., Binder, J., Hartmann, P., Zeier, W.G., Janek, J., 2017. Capacity fade in solid-state batteries: interphase formation and chemo-mechanical processes in nickel-rich layered oxide cathodes and lithium thiophosphate solid electrolytes. Chem. Mater. 29 (13), 5574-5582.

* Lim, H.-D., Park, J.-H., Shin, H.-J., Jeong, J., Kim, J.T., Nam, K.-W., Jung, H.-G., Chung, K.Y., 2020. A review of challenges and issues concerning interfaces for all-solid-state batteries. Energy Storage Mater. 25, 224-250. https://doi.org/10.1016/j.ensm.2019.10.011.

* Nomura, Y., Yamamoto, K., Hirayama, T., Ohkawa, M., Igaki, E., Hojo, N., Saitoh, K., 2018. Quantitative *Operando* visualization of electrochemical reactions and Li ions in all-solid-state batteries by STEM-EELS with hyperspectral image analyses. Nano Lett. 18 (9), 5892-5898. https://doi.org/10.1021/acs.nanolett.8b02587.

* Oukassi, S., Salot, R., Bazin, A., Secouard, C., Chevalier, I., Poncet, S., Poulet, S., Boissel, J.-M., Geffraye, F., Brun, J., 2019. Millimeter Scale Thin Film Batteries for Integrated High Energy Density Storage. 2019 IEEE International Electron Devices
Meeting (IEDM); IEEE: San Francisco, CA, USA 26.1.1–26.1.4. https://doi.org/
10.1109/IEDM19573.2019.8993483.

Schneider, N.M., Norton, M.M., Mendel, B.J., Grogan, J.M., Ross, F.M., Bau, H.H., 2014.
Electron-water interactions and implications for liquid cell electron microscopy.
J. Phys. Chem. C 118 (38), 22373–22382. https://doi.org/10.1021/jp507400n.

Wang, Z., Santhanagopalan, D., Zhang, W., Wang, F., Xin, H.L., He, K., Li, J., Dudney, N.,
Meng, Y.S., 2016. In situ STEM-EELS observation of nanoscale interfacial
phenomena in all-solid-state batteries. Nano Lett. 16 (6), 3760–3767. https://doi.
org/10.1021/acs.nanolett.6b01119.