Electrochemical analysis of interface structures and functionalization in graphitic carbons for Na-ion and flow battery electrodes

Sarbapalli, Dipobrato

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https://hdl.handle.net/2142/120480 Copy

Description

Title

Electrochemical analysis of interface structures and functionalization in graphitic carbons for Na-ion and flow battery electrodes

Author(s)

Sarbapalli, Dipobrato

Issue Date

2023-01-05

Director of Research (if dissertation) or Advisor (if thesis)

Rodríguez-López, Joaquín

Doctoral Committee Chair(s)

Shoemaker, Daniel

Committee Member(s)

• Braun, Paul
• Zhang, Yingjie

Department of Study

Materials Science & Engineerng

Discipline

Materials Science & Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• graphitic carbon
• graphene
• interfaces
• sodium-ion
• redox flow
• secm
• batteries
• electrodes

Abstract

The current state of energy storage in the world currently relies heavily on the use of relatively mature technologies such as Li-ion batteries. However, with scarcities of raw Li reserves and supply chain constraints, future electrochemical energy storage scenario involves having a diverse set of batteries, each dedicated to its niche application, thereby creating a holistic electrochemical energy storage ecosystem. These new technologies need to be developed with earth-abundant materials such as carbon. The objective of my Ph.D. dissertation is to focus on understanding how carbon interfaces influence electron and ion transfer within two upcoming energy storage technologies: Na-ion (NiBs) and non-aqueous redox flow batteries (NRFBs). Electrochemical analysis of these new systems necessitates robust experimental setups, with the reference electrode often a shortcoming in non-aqueous measurements. Chapter 2 of this thesis describes the use of a polypyrrole solid-state reference which can be utilized across non-aqueous systems, and in harsh oxidizing/reducing environments. To incorporate graphite anodes in Na-ion batteries, Chapter 3 describes a fluorine-surface modifier approach, which stabilizes sodium intercalated graphite structures. Likewise, Chapter 4 compares how interphases evolve in terms of graphite electrode passivation in Li, Na, and K electrolytes, which is critical in understanding performance limitations of Na-ion and K-ion batteries, compared to Li-ion. Chapter 5 focuses on NRFBs; specifically on understanding how interfacial processes affect electron transfer using in situ scanning electrochemical microscopy and atomic force microscopy. Chapter 6 describes a rapid, SECM-based “spot-analysis” approach to obtain a quantitative understanding of electron-transfer kinetics as a function of electrode potential. Finally, Chapter 7 explores the interplay between graphite electrode structure and heterogeneous electron transfer kinetics. In summary, this dissertation is written to improve the understanding of how carbon surface structure and functionalization affect the electron and ion transfer at the electrode-electrolyte interface of nascent battery technologies such as NiBs and NRFBs.

Graduation Semester

2023-05

Type of Resource

Thesis

Copyright and License Information

Copyright Dipobrato Sarbapalli

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