Vadhva, Pooja;
(2023)
Solid State Batteries: Materials and Interfaces.
Doctoral thesis (Ph.D), UCL (University College London).
Preview |
Text
Thesis_Final_UCL_submission.pdf - Accepted Version Download (6MB) | Preview |
Abstract
In recent years, solid-state batteries (SSBs) have garnered not only academic research attention but also of that of the electric vehicle (EV) and consumer electronics industry. The use of a solid electrolyte (SE) in a SSB, in place of the flammable liquid electrolyte (LE) used in conventional lithium-ion batteries (LIBs) could result in improved safety. Additionally, SSBs are promising alternatives to the incumbent LIB which contains a LE, due to their higher energy densities by pairing the SE with lithium (Li) or silicon (Si) negative electrodes (NEs). These offer a ≈10x theoretical energy density compared to the graphite NE used in LIBs. However, SSBs are plagued by a unique set of challenges which must be overcome to enable the widespread adoption of this technology: solid-solid interfaces which are highly resistive, slow kinetics, and the formation of interfacial voids leading to Li penetration, which ultimately results in capacity loss and low cycle life. In this work, electrochemical testing, physical characterisation and an electrochemo-mechanical (echem-mech) model is used to investigate and analyse the solid-solid interface, predominantly at the NE|SE interface. First, experimental testing of a commercial thin film Si based SSB is used to parameterise and validate an echem-mech model at the continuum level. Then, the validated model is used to explore the interplay between electrochemistry and mechanics by probing the relationship and between C-rate, applied pressure and capacity on the stress-strain response of the cell. Complex evolution of concentration gradients at high C-rates is found to influence the internal stresses and could point towards sites for fracture propagation within the electrode. Finally, this thesis addresses a key shortcoming of lithium phosphorus oxynitride (LiPON) SE - the requirement for vacuum deposition techniques, to a new non-crystalline (NC) material albeit synthesised using scalable processing methods. Electrochemical testing and physical characterisation of this material Li2.8AlP1.25Ox (LAPO) and its stability against Limetal for use in an “anode-free” battery is explored. The methods and characterisation tools presented in this thesis are designed so that they can be implemented for future testing across different SE battery systems.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Solid State Batteries: Materials and Interfaces |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | © The Author(s). This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10173526 |
Archive Staff Only
 |
View Item |
