Li4Ti5O12: A Visible-to-Infrared Broadband Electrochromic Material for Optical and Thermal Management

Jyotirmoy Mandal, Sicen Du, Martin Dontigny, Karim Zaghib, Nanfang Yu, Yuan Yang

Research output: Contribution to journalArticlepeer-review

108 Scopus citations

Abstract

Broadband electrochromism from visible to infrared wavelengths is attractive for applications like smart windows, thermal camouflage, and temperature control. In this work, the broadband electrochromic properties of Li4Ti5O12 (LTO) and its suitability for infrared camouflage and thermoregulation are investigated. Upon Li+ intercalation, LTO changes from a wide bandgap semiconductor to a metal, causing LTO nanoparticles on metal to transition from a super-broadband optical reflector to a solar absorber and thermal emitter. Large tunabilities of 0.74, 0.68, and 0.30 are observed for the solar reflectance, mid-wave infrared (MWIR) emittance, and long-wave infrared (LWIR) emittance, respectively, with a tunability of 0.43 observed for a wavelength of 10 µm. The values exceed, or are comparable to notable performances in the literature. A promising cycling stability is also observed. MWIR and LWIR thermography reveal that the emittance of LTO-based electrodes can be electrochemically tuned to conceal them amidst their environment. Moreover, under different sky conditions, LTO shows promising solar heating and subambient radiative cooling capabilities depending on the degree of lithiation and device design. The demonstrated capabilities of LTO make electrochromic devices based on LTO highly promising for infrared-camouflage applications in the defense sector, and for thermoregulation in space and terrestrial environments.

Original languageEnglish (US)
Article number1802180
JournalAdvanced Functional Materials
Volume28
Issue number36
DOIs
StatePublished - Sep 5 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

Keywords

  • electrochromism
  • radiative cooling
  • solar heating
  • super-broadband
  • thermal camouflage

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