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Stretchable and Transparent Ionogels with High Thermoelectric Properties
Author(s) -
Fang Yuanlai,
Cheng Hanlin,
He Hao,
Wang Shan,
Li Jianmin,
Yue Shizhong,
Zhang Lei,
Du Zongliang,
Ouyang Jianyong
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202004699
Subject(s) - materials science , thermoelectric effect , ionic liquid , thermoelectric materials , composite material , elastomer , dicyanamide , flexible electronics , bioelectronics , figure of merit , ionic bonding , seebeck coefficient , thermal conductivity , nanotechnology , optoelectronics , organic chemistry , ion , physics , thermodynamics , chemistry , biosensor , catalysis
Stretchable electronic materials and devices have important applications in flexible electronic systems including wearable electronics and bioelectronics. Convenient electricity generation such as thermoelectric conversion is required for the flexible electronic systems. Hence, it is development of high‐performance thermoelectric materials with high mechanical stretchability would be highly desirable. Here, stretchable and transparent ionogels with high thermoelectric properties are demonstrated. The ionogels made of elastomeric waterborne polyurethane and 1‐ethyl‐3‐methylimidazolium dicyanamide (EMIM:DCA, an ionic liquid) are prepared by solution processing. Their mechanical and electrical properties depend on the loading of EMIM:DCA. The ionogels with 40 wt% EMIM:DCA can have a high mechanical stretchability of up to 156%, low tensile strength of 0.6 MPa, and low Young's modulus of 0.6 MPa. They also exhibit a high ionic thermovoltage of 34.5 mV K −1 , high ionic conductivity of 8.4 mS cm −1 and low thermal conductivity of 0.23 W m −1 K −1 at a relative humidity of 90%. As a result, it can have a high ionic figure of merit (ZT i ) of 1.3 ± 0.2. Both the thermovoltage and the ZT i value are the highest for stretchable thermoelectric materials. They can be used in ionic thermoelectric capacitors to convert heat into electricity.