Green synthesis of LiFePO4/graphene coated Carbon Fiber cathodes for high performance structural batteries
Typ
Examensarbete för masterexamen
Program
Publicerad
2022
Författare
Li, Zhaoyang
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Carbon fibers (CF), also known as graphite fibers, can be used as multifunctional
conductive electrodes in "structural batteries" that simultaneously store electrical
energy and carry mechanical loads without additional current collectors. However,
there are several challenges in the commercialization of structural batteries. For example,
CF-based cathode composites usually suffer from their low energy capacity
due to the poor adhesion of active materials on CF surface, and the current fabrication
techniques (such as blade coating or spray coating) need to use toxic organic
solvents such as N-methyl pyrrolidone (NMP).
In this thesis, we report a green approach that utilizes electrophoretic deposition
(EPD) to fabricate novel cathode composites consisting of lithium iron phosphate
(LiFePO4) and graphene nanosheets. Ethanol was used as a green solvent to replace
NMP. Meanwhile, Different commercial graphene materials, including 3 kinds of
graphene nanoplatelets, 4 kinds of reduced graphene oxide were tested and systematically
compared with our homemade graphene. Most of the graphene additives can
significantly improve our structural battery performance, with the highest specific
capacity of 125 mAhg1 and over 80% retention at 2C over 500 cycles. Morphological
and structural analyses were conducted by scanning electron microscopy (SEM) and
Raman spectroscopy to further understand how the surface and quality of different
kinds of graphene can impact the relative battery performance.
Beskrivning
Ämne/nyckelord
Green , Structural battery , Graphene , Electrophoretic deposition