Anodic Electrochromic Nickel Oxide Thin Films: Decay of Charge Density upon Extensive Electrochemical Cycling
2016 (English)In: CHEMELECTROCHEM, ISSN 2196-0216, Vol. 3, no 2, 266-275 p.Article in journal (Refereed) PublishedText
Electrochromic (EC) Ni oxide thin films are a critical component in the smart windows. However, long-term decay of the EC performance in aprotic electrolytes is persistent and poorly understood, and it is difficult to assess lifetimes of EC devices. Here we report on charge density decline upon electrochemical cycling. The charge density decay was modeled with a power law or, alternatively, a stretched exponential; both models describe a rapid drop of charge density during the first hundreds of cycles and a subsequent slower decline. The decay is independent of film composition and applied potential range as long as the upper limit of the potential is 4.4V vs. Li/Li+. Our decay models are interpreted in terms of dispersive chemical reaction kinetics and point at ion diffusion as the rate-limiting step. Power-law exponents are consistent with diffusion. The results provide a framework for evaluating EC durability of Ni-oxide-based thin films and may be important for assessing the durability of EC devices.
Place, publisher, year, edition, pages
2016. Vol. 3, no 2, 266-275 p.
degradation kinetics, electrochromism, nickel oxide, power law, stretched exponential
IdentifiersURN: urn:nbn:se:uu:diva-282493DOI: 10.1002/celc.201500457ISI: 000371254600011OAI: oai:DiVA.org:uu-282493DiVA: diva2:917090
FunderEU, European Research Council, 267234