Journal of Materials Chemistry A
Paper
the diffusion-controlled process. As can be seen in Fig. 10, the
Re is almost the same for the cells with different cathode
materials, indicating that there is no signicant change in the
ionic conductivity of the electrolyte or mobility of the ions with
the different cathode-based cells during the cycling process.
The charge transfer resistance (Rct) varies with different cath-
odes: 600 U for the PTPA electrode and only 160 U for PDDP.
And the reduced charge transfer resistance of PDDP may be
ascribed to the delicate molecular structures and the high free
radical density, which leads to charge migration occurring
smoothly along the polymer chain. The smooth charge migra-
tion for PDDP compared to PTPA was also proven by the UV-Vis
spectra (as displayed in Fig. 3). In addition, the smaller particles
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4. Conclusions
PDDP with a high free radical density structure has been rstly
applied as a cathode material, and has been shown to present
two well-dened plateaus, with quite a high capacity of
129.1 mA h gꢀ1. Moreover, the discharge capacity of PDDP
retained over 110.6 mA h gꢀ1 aer 50 cycles, which was still
higher than the initial capacity of PTPA. UV-Vis spectra and EIS
tests illustrated the smoother charge migration in the PDDP
polymer bulk than in that of PTPA, which was attributed to the
intensive free radical density structure and the improved
morphology of PDDP. The excellent electrochemical perfor-
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the design and preparation of a high capacity cathode with a
high free radical density structure via increasing the number of
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Acknowledgements
The authors gratefully thank the National Natural Science
Foundation of China (NSFC, no. 51003095, no. 51103132) and
Research on Public Welfare Technology Application Projects of
Zhejiang Province, China (2010C31121) for nancial support.
This work also was supported by the analysis and testing
foundation of Zhejiang University of Technology.
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20088 | J. Mater. Chem. A, 2014, 2, 20083–20088
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