A. Li Bassi

C. Castiglioni

G. Bussetti

L. Duo'

M. Tommasini

R. Yivlialin

English

Archivio istituzionale della ricerca - Politecnico di Milano

Disclosing the early stages of electrochemical anions intercalation in graphite by a combined AFM/STM investigationR. Yivlialin1*, G. Bussetti1, A. Li Bassi2, C. Castiglioni3, M. Tommasini3 and L. Duò11 Dept. of Physics, Politecnico di Milano, p.za Leonardo da Vinci 32, 20133, Milano, Italy, 2 Dept. of Energy, Politecnico di Milano, v. Ponzio 34/3 20133, Milano, Italy3Dept. of Chemistry, Materials and Chemical Engineering, Politecnico di Milano, p.za Leonardo da Vinci 32, 20133, Milano, Italy.* Presenting Author: rossella.yivlialin@polimi.it abstractHigh-quality and wide-size graphene sheets with single- or few-layer thickness and low defectivity are crucial for the future development of graphene-based nanoelectronics and nano-electromechanical systems. Different strategies can be used for graphite delamination and graphene production: mechanical, chemical and electrochemical. The chemical/electrochemical strategies ensure large amounts of graphene and a good quality of the products. So far, optimization of the procedural protocols was generally undertaken through a systematic investigation of the delaminated graphene flakes, while less attention has been paid to the graphite crystal in the solution. The current state of research in this field requires a better comprehension of the nanoscale molecular mechanisms involved during the ions intercalation inside the crystal, which represents the first step towards the crystal swelling and the subsequent graphite exfoliation. This local investigation can be tackled by a combination of scanning probe microscopies (with atomic resolution) with specific chemical monitoring techniques. A choice is offered by the so-called electrochemical atomic force and scanning tunnelling microscopes (EC-AFM and EC-STM, respectively). However, EC-STM has been rarely if not at all exploited for a nanoscale investigation of the first intercalation stages so far, despite the inherent improvement in spatial resolution that it offers compared to EC-AFM. This fact is probably due to the intrinsic difficulty in piloting the STM tip during ions intercalation.  	In this work, we monitor the graphite surface changes as a function of the electrochemical potential by both EC-AFM and EC-STM coupled with cyclic voltammetry. Following this strategy, we disclose the surface modifications encountered during the early stages of ion intercalation, for different electrolytes: surface faceting, step erosion, terrace damages, and nano-protrusions, all affecting the graphite surface and therefore the exfoliation process. We believe that, within the current debate on the delamination of layered crystals, our findings represent a key step towards a full investigation of the intercalation process in graphite. 

Disclosing the early stages of electrochemical anions intercalation in graphite by a combined AFM/STM investigation

https://re.public.polimi.it/bitstream/11311/1239058/1/abstract_ElecNano7.doc

Disclosing the early stages of electrochemical anions intercalation in graphite by a combined AFM/STM investigation

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Archivio istituzionale della ricerca - Politecnico di Milano