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A High Areal Capacity Flexible Lithium‐Ion Battery with a Strain‐Compliant Design
Author(s) -
Gaikwad Abhinav M.,
Khau Brian V.,
Davies Greg,
Hertzberg Benjamin,
Steingart Daniel A.,
Arias Ana Claudia
Publication year - 2015
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201401389
Subject(s) - materials science , battery (electricity) , lithium titanate , lithium ion battery , electrode , electrochemistry , lithium (medication) , cobalt oxide , ultimate tensile strength , dielectric spectroscopy , flexibility (engineering) , composite material , oxide , nanotechnology , power (physics) , metallurgy , mathematics , chemistry , medicine , physics , statistics , quantum mechanics , endocrinology
Early demonstrations of wearable devices have driven interest in flexible lithium‐ion batteries. Previous demonstrations of flexible lithium‐ion batteries trade off between low areal capacity, poor mechanical flexibility and/or high thickness of inactive components. Here, a reinforced electrode design is used to support the active layers of the battery and a freestanding carbon nanotube (CNT) layer is used as the current collector. The supported architecture helps to increase the areal capacity (mAh cm ‐2 ) of the battery and improve the tensile strength and mechanical flexibility of the electrodes. Batteries based on lithium cobalt oxide and lithium titanate oxide shows excellent electrochemical and mechanical performance. The battery has an areal capacity of ≈1 mAh cm ‐2 and a capacity retention of around 94% after cycling the battery for 450 cycles at a C/2 rate. The reinforced electrode has a tensile strength of ≈5.5–7.0 MPa and shows excellent capacity retention after repeatedly flexing to a bending radius ranging from 45 to 10 mm. The relationships between mechanical flexing, electrochemical performance, and mechanical integrity of the battery are studied using electrochemical cycling, electron microscopy, and electrochemical impedance spectroscopy (EIS).