Preparation of Graphene Liquid Cells for the Observation of Lithium-ion Battery Material

Summary

Here, we present a protocol for the fabrication and preparation of a graphene liquid cell for in situ transmission electron microscopy observation, along with a synthesis of electrode materials and electrochemical battery cell tests.

Abstract

In this work, we introduce the preparation of graphene liquid cells (GLCs), encapsulating both electrode materials and organic liquid electrolytes between two graphene sheets, and the facile synthesis of one-dimensional nanostructures using electrospinning. The GLC enables in situ transmission electron microscopy (TEM) for the lithiation dynamics of electrode materials. The in situ GLC-TEM using an electron beam for both imaging and lithiation can utilize not only realistic battery electrolytes, but also the high-resolution imaging of various morphological, phase, and interfacial transitions.

Introduction

Recently, the consumption of energy has constantly increased, as well as the importance of high-performance energy storage devices. To meet such a demand, the development of lithium-ion batteries that have a high energy density, durability, and safety is necessary^1,2. In order to develop batteries with superior properties, a fundamental understanding of energy storage mechanisms during battery operation is essential^3,4,5_.

In situ transmission electron microscopy (TEM) pr....

Protocol

1. Synthesis of SnO₂ Nanotubes by Electrospinning and Subsequent Heat Treatment¹⁷

1. Prepare an electrospinning solution.
   1. Dissolve 0.25 g of tin chloride dihydrate in a solvent mixture of 1.25 g of ethanol and 1.25 g of dimethylformamide (DMF) at room temperature (RT, 25 °C).
   2. After stirring for 2 h, add 0.35 g of polyvinylpyrrolidone (PVP) to the electrospinning solution and stir the mixture for another 6 h.
2. Perform an electrospinning of the Sn precursor/PVP composite nanofibers.
   1. When the electrospinning solution is well prepared, wash the rectangular, flexible ....

Results

SnO₂ nanotubes were fabricated by electrospinning and subsequent calcination, during which the nanotubular and porous structures could be seen clearly, according to the SEM image (Figure 3a). Such a nanotubular structure comes from the decomposition of PVP, while the Sn precursor in the core is moved outward due to the Kirkendall effect^17,18. Additionally, Ostwald ripening .......

Discussion

There are critical steps within the protocol. First, the transfer of the graphene onto the TEM grid needs the researchers' careful attention. It is important to handle the grids with tweezers and not damage any of grids, for instance by destroying the amorphous carbon membrane or bending the frame. These kinds of damages will result in a poor coverage of the graphene and affect the number of liquid pockets. In addition, placing the upper grid at the right position is critical. As described in the protocol, the top gr.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Tin chloride dihyrate	Sigma Aldrich	CAS 10025-69-1	In a glass bottle
Ethanol	Merck	CAS 64-17-5	In a glass bottle
Dimethylformamide	Sigma Aldrich	CAS 68-12-2	In a glass bottle
Polyvinylpyrrolidone	Sigma Aldrich	CAS 9003-39-8	In a plastic bottle
Cell tester	KOREA THERMO-TECH	Maccor Series 4000
Cell tester 2	WonaTech	WBCS4000
Sodium perchlorate	Sigma Aldrich	CAS 7601-89-0	In a glass bottle
25 gauge needle	Hwa-In Science Ltd.
1.3 M of lithium hexafluorophosphate (LiPF6) dissolved in EC/DEC with 10 wt% of FEC	PANAX ETEC		In a stainless steel bottle
Propylene carbonate	Sigma Aldrich	CAS 108-32-7	In a glass bottle
Super P Carbon Black	Alfa-Aesar	CAS 1333-86-4	In a glass bottle
Cell components (bottom cell, top cell, separator, gasket, spring, spacer)	Wellcos Corporation
Cell punch	Wellcos Corporation
Glove Box	Moisture Oxygen Technology (MOTEK)
Box Furnace	Naytech	Vulcan 3-550
Electrospinning device	NanoNC
Hydrofluoric acid	Junsei	84045-0350	85%
Cu foil	Alfaaesar	38381	Copper Thinfoil, 0.0125mm thick, 99.9%
Holy carbon Au grid	SPI	Quantifoil R2/2 Micromachined Holey Carbon Grids, 300 Mesh Gold	Quantifoil R2/2 Micromachined Holey Carbon Grids, 300 Mesh Gold
Isoprophyl alchol	Sigmaaldrich	W292907	99.70%
Ammonium persulfate	Sigmaaldrich	248614	98%
Transmission electron microscope (TEM)	JEOL	JEOL JEM 3010	300 kV
Chemical vapor depistion (CVD)	Scientech
Charge coupled device (CCD)	Gatan	Orius SC200
Plasma Cleaner	Femtoscience	VITA
Electrospinning program	NanoNC	NanoNC eS- robot