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Iron Phosphate Coated Flexible Carbon Nanotube Fabric as a Multifunctional Cathode for Na‐Ion Batteries
Author(s) -
Ren Xiaolei,
Turcheniuk Kostiantyn,
Lewis Daniel,
Fu Wenbin,
Magasinski Alexandre,
Schauer Mark W.,
Yushin Gleb
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201703425
Subject(s) - carbon nanotube , materials science , iron phosphate , cathode , nanotechnology , phosphate , ion , carbon fibers , chemical engineering , lithium iron phosphate , nanotube , electrode , electrochemistry , composite material , chemistry , composite number , organic chemistry , engineering
Conventional slurry casted electrodes cannot stand high loads or be repeatedly flexed or bent without being fractured, which inhibits their use in flexible batteries. Carbon nanotube (CNT) fabric exhibits a paramount mechanical stability and, due to its porosity, can additionally accommodate an active material within its structure. While solution‐based protocols cannot achieve conformal coatings of active materials, chemical vapor deposition (CVD) gives a unique opportunity to control and vary the thickness and homogeneity of the coating. Herein, a conformal CVD coating of amorphous iron (III) phosphate ( a ‐FePO 4 , FP) on flexible CNT fabric and its ability to reversibly accommodate large radius Na ions is reported. The freestanding binder‐free CNT@FP electrodes exhibit high‐rate capabilities and exceptional cycle stabilities with 98% of retention of initial capacity after 100 cycles. Such electrodes additionally demonstrate high mechanical stability under high loads, remarkable bending characteristics, and modulus of toughness (12 MJ m −3 ) exceeding that of Al. The presented concept of flexible CNT@FePO 4 electrodes with high load‐bearing characteristics opens new perspectives toward the formation of light‐weight, flexible, multifunctional Na‐ion battery electrodes based on abundant materials.