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    Structural and Interfacial Engineering of 2,5-Dihydroxy-1,4-Benzoquinone Coordination-Polymer Cathodes for Sustainable Lithium-Ion Batteries
    (University of Waterloo, 2026-05-14) Wang, Yonglin
    Carbonyl-based organic compounds are one of the most promising sustainable cathode materials for next-generation lithium-ion batteries due to their highly reversible C=O redox center, high theoretical capacity, structural tunability, and potential derivation from abundant or biomass-related feedstocks. However, their practical deployment has been limited by intrinsically high solubility in conventional carbonate- and ether-based electrolytes. Dissolution-driven loss of active material not only leads to rapid capacity fading but also induces serious shuttle effect, self-discharge, and parasitic reactions. Therefore, suppressing dissolution is an essential prerequisite for achieving long-term stability and practical energy density in organic cathodes. Among various carbonyl-based candidates, 2,5-dihydroxy-1,4-benzoquinone (DHBQ) is attractive because of its high theoretical capacity (383 mAh g⁻¹), simple structure, and potential renewability. Yet DHBQ is highly soluble in common organic electrolytes, preventing stable cycling. In this thesis, coordination polymer (CP) synthesis was employed as the primary strategy to reduce the solubility of carbonyl-based cathodes. By incorporating redox-active quinone units into coordination frameworks, CP structures increase the energetic barrier for molecular detachment and solvation, thereby effectively suppressing dissolution. Moreover, CPs can be synthesized through relatively simple coordination reactions using accessible precursors, offering practical feasibility and potential scalability. In Chapter 3, a metastable quinone-based coordination polymer, Co-DHBQ·2H₂O, was investigated as a transition-metal-redox cathode. When cycled between 0.7–3.0 V, the electrodes undergo a reversible four-electron transfer process involving both DHBQ and Co redox reactions. Initial side reactions, including SEI formation and benzene-ring lithiation, lead to a high first-cycle capacity of 783 mAh g⁻¹. After stabilization, the cathode delivers 199 mAh g⁻¹ after 750 cycles, with 84% capacity retention between the 100th and 750th cycles. Structural analyses reveal that coordinated water molecules form strong hydrogen bonds (up to -40.5 kJ mol⁻¹) that stabilize the layered framework and preserve structural integrity during cycling. However, excessive lithiation at low voltages induces structural damage due to the metastable nature of the hydrogen-bonded layers. Comparative studies with anhydrous Co-DHBQ confirm that coordinated water is critical for maintaining structural integrity, enabling reversible Li⁺ accommodation, and achieving long-term electrochemical stability. In Chapter 4, a lithium-based, transition-metal-free Li₂DHBQ cathode was investigated to reduce mass penalty while maintaining low solubility. Although Li₂DHBQ exhibits extremely low solubility in the electrolyte, severe morphological degradation of the active material was identified as the primary origin of poor cycling stability. Repeated lithiation and delithiation induce particle fracture and progressive disruption of electronic percolation pathways, leading to capacity fading independent of dissolution effects. To address this issue, the discharge cutoff voltage was lowered to 0.5 V to promote electrolyte reduction and in situ formation of a protective solid electrolyte interphase (SEI) layer on the Li₂DHBQ surface. This strategy significantly enhanced morphological stability and improved electrochemical performance. When cycled between 0.5–3.0 V at 500 mA g⁻¹, the cathode maintained a capacity of 170 mAh g⁻¹ after 200 cycles, with a low decay rate of 0.16% per cycle. Furthermore, a preconditioning strategy in which the electrode was first cycled at 0.5 V for 20 cycles to form the SEI layer, followed by cycling within the normal 1.5–3.0 V range at 500 mA g⁻¹, resulted in even better performance, retaining 187 mAh g⁻¹ at the 200th cycle. In contrast, a cell cycled only within 1.5–3.0 V retained merely 87 mAh g⁻¹ after 200 cycles. These results demonstrate that controlled SEI formation effectively reinforces morphological stability, mitigates structural degradation, and substantially improves long-term cycling performance once dissolution has been suppressed. In Chapter 5, we build upon Chapter 4 and introduce a more controlled strategy for cathode surface stabilization through the incorporation of fluoroethylene carbonate (FEC) as a CEI-forming additive. The addition of 1 wt.% FEC promotes the formation of a robust CEI layer that significantly suppresses particle pulverization and enhances structural integrity during cycling. SEM and TEM analyses reveal that the optimized CEI layer is relatively uniform and approximately 30 nm thick, effectively mitigating active material degradation. As a result, the Li₂DHBQ cathode with 1% FEC exhibits substantially improved electrochemical performance. When cycled at 500 mA g⁻¹, the electrode retains 185 mAh g⁻¹ after 200 cycles with a low-capacity decay rate of 0.049% per cycle, compared to 81 mAh g⁻¹ and a decay rate of 0.302% per cycle for the FEC-free battery. In addition to enhanced cycling stability, the FEC-containing cell demonstrates superior rate capability, supported by a dominant capacitive contribution of up to 93.7%, indicating accelerated surface-controlled charge storage behavior. These findings confirm that CEI engineering via controlled additive incorporation effectively stabilizes the electrode structure, suppresses interfacial degradation, and optimizes charge storage kinetics once dissolution has been mitigated. The results highlight the importance of interphase design in enabling stable and high-rate organic cathode systems. Beyond electrochemical stability, in Chapter 6 this work also addresses sustainability and end-of-life considerations. A proof-of-concept recycling strategy for Li₂DHBQ-based cathodes was developed using solubility-selective disassembly. By exploiting the solubility contrast among active material, conductive additive, binder, and current collector, approximately 95% of Li₂DHBQ could be recovered under mild conditions. This result highlights the intrinsic compatibility of organic cathode systems with low-energy and environmentally benign recycling pathways. Overall, through coordination polymer immobilization, interfacial engineering, and recyclability-oriented electrode design, this work provides coherent design principles for developing stable, insoluble, and recyclable carbonyl-based cathodes toward sustainable lithium-ion battery technologies.
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    Population-based estimate of hepatitis C virus prevalence in Ontario, Canada
    (Public Library of Science, 2018-01-23) Bolotin, Shelly; Feld, Jordan J.; Garber, Gary; Wong, William W. L.; Guerra, Fiona M.; Mazzulli, Tony
    Background Hepatitis C virus (HCV) is the most burdensome infectious illness in Canada. Current screening strategies miss a significant proportion of cases, leaving many undiagnosed. Elevated HCV prevalence in those born between 1945 and 1965 has prompted calls for birth-cohort screening in this group. However, Canada lacks population-level data to support this recommendation. We performed a serosurvey to obtain population-based HCV prevalence estimates in Ontario residents born between 1945-1974, to generate evidence for birth-cohort screening recommendations. Methods We tested anonymized residual sera in five-year age-sex bands from Ontario for anti-HCV antibody. We performed descriptive epidemiological analysis and used a logistic regression model to determine HCV risk-factors. Result Of 10,006 sera analyzed, 155 (1.55%, 95% confidence interval (CI) 1.32, 1.81) were positive for HCV antibody. Individuals born between 1950–1964 had a significantly higher combined prevalence of 1.92% (95% CI 1.56, 2.34) compared to 1.14% (95% CI 0.69, 1.77) (p = 0.04) for those born between 1970–1974. For males, comprising 107/155 (69.03%) of positive samples, the highest prevalence was 3.00% (95% CI 1.95, 4.39) for the 1960–1964 birth-cohort. For females, the highest prevalence was 1.56% (95% CI 0.83, 2.65) for those born between 1955–1959. Male sex was significantly associated with positive HCV serostatus. Interpretation HCV prevalence in Ontario is highest among those in this birth cohort, and higher than previous estimates. The prevalence estimates presented in our study provide important data to underpin birth-cohort screening recommendations.
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    Evaluating authentication options for mobile health applications in younger and older adults
    (Public Library of Science, 2018-01-04) Grindrod, Kelly; Khan, Hassan; Hengartner, Urs; Ong, Stephanie; Logan, Alexander G.; Vogel, Daniel; Geboyts, Robert; Yang, Jilan
    Objective Apps promoting patient self-management may improve health outcomes. However, methods to secure stored information on mobile devices may adversely affect usability. We tested the reliability and usability of common user authentication techniques in younger and older adults. Methodology Usability testing was conducted in two age groups, 18 to 30 years and 50 years and older. After completing a demographic questionnaire, each participant tested four authentication options in random order: four-digit personal identification number (PIN), graphical password (GRAPHICAL), Android pattern-lock (PATTERN), and a swipe-style Android fingerprint scanner (FINGERPRINT). Participants rated each option using the Systems Usability Scale (SUS). Results A total of 59 older and 43 younger participants completed the study. Overall, PATTERN was the fastest option (3.44s), and PIN had the fewest errors per attempt (0.02). Participants were able to login using PIN, PATTERN, and GRAPHICAL at least 98% of the time. FINGERPRINT was the slowest (26.97s), had an average of 1.46 errors per attempt, and had a successful login rate of 85%. Overall, PIN and PATTERN had higher SUS scores than FINGERPRINT and GRAPHICAL. Compared to younger participants, older participants were also less likely to find PATTERN to be tiring, annoying or time consuming and less likely to consider PIN to be time consuming. Younger participants were more likely to rate GRAPHICAL as annoying, time consuming and tiring than older participants. Conclusions On mobile devices, PIN and pattern-lock outperformed graphical passwords and swipe-style fingerprints. All participants took longer to authenticate using the swipe-style fingerprint compared to other options. Older participants also took two to three seconds longer to authenticate using the PIN, pattern and graphical passwords though this did not appear to affect perceived usability.
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    Behavioural patterns only predict concurrent BMI status and not BMI trajectories in a sample of youth in Ontario, Canada
    (Public Library of Science, 2018-01-02) Laxer, Rachel E.; Cooke, Martin; Dubin, Joel A.; Brownson, Ross C.; Chaurasia, Ashok; Leatherdale, Scott T.
    Background Youth are engaging in multiple risky behaviours, increasing their risk of overweight, obesity, and related chronic diseases. The objective of this study was to examine the effect of engaging in unique clusters of unhealthy behaviours on youths' body mass index (BMI) trajectories. Methods This study used a linked-longitudinal sample of Grades 9 and 10 students (13 to 17 years of age) participating in the COMPASS host study. Students reported obesity-related and other risky behaviours at baseline and height and weight (to derive BMI) at baseline (2012/2013) and annually for 2 years post-baseline (2013/14 and 2014/15). Students were grouped into behavioural clusters based on response probabilities. Linear mixed effects models, using BMI as a continuous outcome measure, were used to examine the effect of engaging in clusters of risky behaviours on BMI trajectories. Results There were significant differences in BMI of the four behavioural clusters at baseline that remained consistent over time. Higher BMI values were found among youth classified at baseline to be Typical High School Athletes (β = 0.232 kg/m2, [confidence interval (CI): 0.03–0.50]), Inactive High Screen-User (β = 0.348 kg/m2, CI: 0.11–0.59) and Moderately Active Substance Users (β = 0.759 kg/m2, CI: 0.36–1.15) compared to students classified as Health Conscious. Despite these baseline differences, BMI appeared to increase across all behavioural clusters annually by the same amount (β = 0.6097 kg/m2, (CI) = 0.57–0.64). Conclusions Although annual increases in BMI did not differ by behavioural clusters, membership in a particular behavioural cluster was associated with baseline BMI, and these differences remained consistent over time. Results indicate that intervening and modifying unhealthy behaviours earlier might have a greater impact than during adolescence. Health promotion strategies targeting the highest risk youth as they enter secondary school might be promising means to prevent or delay the onset of obesity.
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    Efficacy of a biomechanically-based yoga exercise program in knee osteoarthritis: A randomized controlled trial
    (Public Library of Science, 2018-04-17) Kuntz, Alexander B.; Chopp-Hurley, Jaclyn N.; Brenneman, Elora C.; Karampatos, Sarah; Wiebenga, Emily G.; Adachi, Jonathan D.; Noseworthy, Michael D.; Maly, Monica R.
    Objective Certain exercises could overload the osteoarthritic knee. We developed an exercise program from yoga postures with a minimal knee adduction moment for knee osteoarthritis. The purpose was to compare the effectiveness of this biomechanically-based yoga exercise (YE), with traditional exercise (TE), and a no-exercise attention-equivalent control (NE) for improving pain, self-reported physical function and mobility performance in women with knee osteoarthritis. Design Single-blind, three-arm randomized controlled trial. Setting Community in Southwestern Ontario, Canada. Participants A convenience sample of 31 women with symptomatic knee osteoarthritis was recruited through rheumatology, orthopaedic and physiotherapy clinics, newspapers and word-of-mouth. Interventions Participants were stratified by disease severity and randomly allocated to one of three 12-week, supervised intervention. YE included biomechanically-based yoga exercises; TE included traditional leg strengthening on machines; and NE included meditation with no exercise. Participants were asked to attend three 1-hour group classes/sessions each week. Measurements Primary outcomes were pain, self-reported physical function and mobility performance. Secondary outcomes were knee strength, depression, and health-related quality of life. All were assessed by a blinded assessor at baseline and immediately following the intervention. Results The YE group demonstrated greater improvements in KOOS pain (mean difference of 22.9 [95% CI, 6.9 to 38.8; p = 0.003]), intermittent pain (mean difference of -19.6 [95% CI, -34.8 to -4.4; p = 0.009]) and self-reported physical function (mean difference of 17.2 [95% CI, 5.2 to 29.2; p = 0.003]) compared to NE. Improvements in these outcomes were similar between YE and TE. However, TE demonstrated a greater improvement in knee flexor strength compared to YE (mean difference of 0.1 [95% CI, 0.1 to 0.2]. Improvements from baseline to follow-up were present in quality of life score for YE and knee flexor strength for TE, while both also demonstrated improvements in mobility. No improvement in any outcome was present in NE. Conclusions The biomechanically-based yoga exercise program produced clinically meaningful improvements in pain, self-reported physical function and mobility in women with clinical knee OA compared to no exercise. While not statistically significant, improvements in these outcomes were larger than those elicited from the traditional exercise-based program. Through this may suggest that the yoga program may be more efficacious for knee OA, future research studying a larger sample is required.