Kai Zhang,1 Yuxiang Hu,1,2 Lianzhou Wang,1,2 Jiyu Fan,3 Michael J. Monteiro,1 Zhongfan Jia1*

 

1. Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane QLD 4072, Australia
2. School of Chemical Engineering, University of Queensland, Brisbane QLD 4072, Australia
3. Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China

 

Nitroxide polymers poly (TEMPO methacrylate) can undergoes a fast reversible redox process (TEMPO0/+), which make it a suitable cathode material of lithium battery[1]. Currently, in most studies, a high polydispersity PTMA is synthesized via normal radical polymerization. In this work we utilized single electron transfer-living radical polymerization (SET-LRP) to synthesize poly(2,2,6,6-tetramethylpiperidine methacrylate) (PTMPM) with degree of polymerization ranging from 66 to 703, after oxidation giving poly(TEMPO methacrylate) (PTMA) with the highest molecular weight of 169KDa and disparity (i.e. Ð) of 1.35.  Using these PTMA polymers as active materials with 25 wt% in electrode composite showed strong molecular weight dependence of electrochemical properties. PTMA with higher molecular weight had the lower solubility and showed higher specific discharging capacity and better cycling stability. It suggests the importance to synthesize nitroxide radical polymers with high molecular weight to minimize their dissolution into electrolyte for optimum battery performance[2].

Figure 1: capacity of lithium/nitroxide polymer battery with different Mw PTMA as cathode material.

 

References

[1]. Zhang, Kai, Michael J. Monteiro, and Zhongfan Jia. "Stable organic radical polymers: synthesis and applications." Polymer Chemistry 7.36 (2016): 5589-5614.

[2]. Zhang, Kai, et al. "The impact of the molecular weight on the electrochemical properties of poly (TEMPO methacrylate)." Polymer Chemistry 8.11 (2017): 1815-1823.