Impact of Carbon Structure and Morphology on the ElectrochemicalPerformance of LiFePO4/C Composites
The electrochemical performance of LiFePO{sub 4}/C composites in lithium cells is closely correlated to pressed pellet conductivities measured by AC impedance methods. These composite conductivities are a strong function not only of the amount of carbon, but of its structure and distribution. Ideally, the amount of carbon in composites should be minimal (less than about 2 wt. %) so as not to decrease the energy density unduly. This is particularly important for plug-in hybrid electric vehicle applications (PHEVs) where both high power and moderate energy density are required. Optimization of the carbon structure, particularly the sp{sup 2}/sp{sup 3} and D/G (disordered/graphene) ratios, improves the electronic conductivity while minimizing the carbon amount. Manipulation of the carbon structure can be achieved via the use of synthetic additives including iron-containing graphitization catalysts. Additionally, combustion synthesis techniques allow co-synthesis of LiFePO{sub 4} and carbon fibers or nanotubes, which can act as 'nanowires' for the conduction of current during cell operation.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE. Assistant Secretary for Energy Efficiency andRenewable Energy. Vehicle Technologies
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 925533
- Report Number(s):
- LBNL-63002; R&D Project: 500302; BnR: VT0301030; TRN: US200809%%790
- Journal Information:
- Journal of Solid State Electrochemistry, Vol. DOI 10.1107/s10008-007-0419-9; Related Information: Journal Publication Date: 09/19/2007
- Country of Publication:
- United States
- Language:
- English
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