A5045149043- Advanced Battery Technologies Research
- Advancements in Battery Materials
- Advanced Battery Materials and Technologies
- Radiation Effects in Electronics
- Supercapacitor Materials and Fabrication
- Extraction and Separation Processes
- Graphite, nuclear technology, radiation studies
- Fiber-reinforced polymer composites
- Recycling and Waste Management Techniques
Dalhousie University
2022-2023
University of Tartu
2023
Dimethyl terephthalate (DMT) is a redox shuttle molecule that leads to unwanted self-discharge of lithium-ion cells. It can be created in situ as breakdown product polyethylene (PET), which surprisingly common polymer for the adhesive tapes found commercial This study investigates shuttling mechanism and electrochemical stability DMT, well its impact on performance LFP/graphite pouch cells with LiFSI LiPF 6 conducting salts. Cyclic voltammetry shows DMT has potential 1.5 V vs Li + /Li active...
Unwanted self-discharge of LFP/AG and NMC811/AG cells can be caused by in situ generation a redox shuttle molecule after formation at elevated temperature with common alkyl carbonate electrolyte. This study investigates the for several electrolyte additives, e.g., vinylene lithium difluorophosphate, measuring additive reduction onset potential, first cycle inefficiency gas evolution during temperatures between 25 70 °C. After formation, is extracted from pouch visual inspection...
Abstract Li-ion pouch cells that have experienced long-term accelerated testing at extreme temperatures exhibited electrolyte permeation through the seals of bag, leading to eventual cell failure due unwetting and impedance growth. Degradation bag material is also noticed. The rate follows an Arrhenius-type behavior can be substantial high (35 wt% y−1 70°C). indicated dependent on volatility solvent. Electrolyte loss mitigated by applying high-temperature epoxy sealant or switching form...
Every commercial Li-ion cell contains several inactive components, most of which are composed polymers. Many these polymer-based such as gaskets, jellyroll tapes, or even current collectors, utilize ester-based plastics. This study presents chemical screening experiments on plastics used in lithium-ion cells, specifically the presence alkoxides, common electrolyte degradation products generated cells without effective additives. These demonstrate that polymers can negatively impact their...
A common degradation product dimethyl-2,5-dioxahexane carboxylate (DMOHC) produced in Li-ion cell electrolytes after ageing is used here as an electrolyte solvent, allowing cells to operate at high temperatures (70 °C and 85 °C) with excellent capacity retention low impedance growth. Viscosity conductivity values are reported for various DMOHC diethyl-2,5-dioxahexane (DEOHC) blends dimethyl carbonate (DMC) diethyl (DEC). Charge-discharge cycling data LiFePO 4 /graphite (LFP), Li[Ni 0.5 Mn...
Abstract Polyethylene terephthalate (PET) tape is widely used by well-known lithium-ion battery manufacturers to prevent electrode stacks from unwinding during assembly. PET selected since it has suitable mechanical and electrical properties, but its chemical stability been largely overlooked. In the absence of effective electrolyte additives, can depolymerize into monomer dimethyl (DMT), which an unwanted redox shuttle that induces significant self-discharge in a cell. This study presents...
This study investigates the influence of jellyroll tape materials on cycle life and self-discharge layered oxide/hard carbon sodium-ion pouch cells. Jellyroll tapes made polyethylene terephthalate (PET) or polypropylene (PP) polymer were used in this study. Severe PET decomposition was observed additive-free electrolyte. The use solid-electrode interphase forming additives suppressed effectively resulted a competitive performance comparable to that cells with PP tape. Replacing led...
It has been shown that electrolyte additives can be highly beneficial to the performance and lifetime of lithium-ion cells. 1,2 However, many are consumed in early cycles, which will affect cycling cell over long-term operation. most relatively early. For example, when ≤2 wt% vinylene carbonate is used Li[Ni 0.33 Mn Co ]O 2 /graphite cells, it during first 200 h 3 Prop-1-ene-1,3-sultone (PES) (VC) among PES useful for suppressing gas formation, VC found form a stable solid-electrolyte...
Olivine LiFePO4 (LFP) has emerged as a compelling alternative to its counterpart, layered Li[Ni x Mn y Co z ]O 2 (NMC), in commercial lithium-ion cells due cost-effectiveness, utilization of abundantly available Fe, and superior safety characteristics. However, LFP/graphite exhibit notable degradation lifetime when subjected high temperatures compared NMC. To address this issue, we explore the efficacy incorporating electrolyte additive Vinylene Carbonate (VC) improve at 70 °C. Through μXRF...
Every commercial lithium-ion cell made by winding or stacking electrodes uses tape to secure the jelly roll. Recently, it has been shown that roll is often out of polyethylene terephthalate (PET) 1 and can dissolve into dimethyl (DMT), a redox shuttle capable inducing self-discharge unless effective electrolyte additives are present. 2 This due ester bonds in PET susceptible methanolysis via methanol lithium methoxide. created situ during battery operation from carbonate (DMC), ubiquitous...
Alkyl dicarbonates are known electrolyte degradation products produced in Li-ion cells that use ethylene carbonate (EC) and dimethyl (DMC) as components. Also referred to dimerization compounds, 2,5-dioxahexanedioate (DMOHC) diethyl (DEOHC), were investigated a possible sole solvent or one component of blended mixture, when mixed with linear carbonates. The viscosities DMOHC DEOHC measured this report compared the predictions Advanced Electrolyte Model 1 , along two alkyl lithium salts other...
Every lithium-ion battery cell produced today that is either wound or stacked contains tape. This tape serves the mechanical purpose of holding together jellyroll electrodes before inserting it into casing, after which no purpose. Battery manufacturers often test inactive parts for their physical parameters, i.e., elongation, water absorption, and temperature resistance. 1 However, chemical stability overlooked. Recently, was demonstrated polyethylene terephthalate (PET) can partially...
Recent studies showed that LFP/graphite cells without additives show higher reversible self-discharge after 500 h of open-circuit voltage (OCV) storage at 40 or 60°C than NMC811/graphite cells. 1 Furthermore, with lithium hexafluorophosphate (LiPF 6 ), the most commonly used conducting salt in lithium-ion batteries, bis(fluorosulfonyl)imide (LiFSI), an alternative temperature stability. 2 Recently, dimethyl terephthalate (DMT) was identified as redox shuttle molecule responsible for unwanted...