Assorted Phenoxyl-Radical Polymers and Their Application in Lithium-Organic Batteries

Abstract

The synthesis and electrochemical characterization of novel polymers bearing phenoxyl-radicals as redox-active side chains is described. The monomers are synthesized from the corresponding phenols and quinones, respectively. These compounds are subsequently poly-merized via ring-opening metathesis polymerization. The electrochemical properties of the phenoxyl-radical polymers are characterized using cyclic voltammetry and the most promising polymer is investigated as active material in a lithium coin-cell, creating the first phenoxyl-lithium battery. These phenoxyl-containing polymers represent interesting anode materials for organic radical and lithium batteries due to their suitable redox-potentials and possibility to create batteries with higher potentials as well as straightforward synthesis procedures.

Sustainable Energy Storage: Recent Trends and Developments toward Fully Organic Batteries

“…A polymer of the 1,1,3,3‐tetramethylisoindolin‐2‐yloxyl radical showed a comparable performance in a lithium‐ion cell, whereas a polyphosphazene bearing an N‐tert ‐butyl‐ N ‐oxylamino phenyl radical unit resulted in a higher initial capacity of 145 mAh g −1 but a capacity drop of 35 % during the first 50 cycles . A phenoxyl radical was used in a polynorbornene in form of tetramethylphenoxyl units, but a built hybrid lithium‐ion cell showed a capacity of only 60 mAh g −1 , losing 20 % capacity over the first 100 cycles …”

“…[123] Aphenoxyl radicalwas used in apolynorbornenei nf orm of tetramethylphenoxyl units, but ab uilt hybrid lithium-ion cell showed ac apacity of only 60 mAh g À1 , losing 20 %c apacity over the first 100 cycles. [124] In conclusion, no new organic radicals that represent promising candidates for organic batteries were revealed recently. Nevertheless, systemsb ased on already established motifs, namely on TEMPOa nd didehydro-PROXYL, were further optimized,i np articular with regard to higher electrical and ionic conductivities.…”

Stable Bifunctional Perylene Imide Radicals for High‐Performance Organic–Lithium Redox‐Flow Batteries

“…The electrochemical properties of 4-hydroxy-2,6-di-tert-butylphenyl-substituted 1 and 2 in dichloromethaneh aveb een investigated by cyclic voltammetry technique (see Figures 2b and S19 in the Supporting Information).A lthough the results obtained in dilute solutiona re not representative of their electrochemical behaviors in an organic-lithium redox-flow battery, they provide valuablei nformationo nt he number of redox eventsa nd their reversibility.A se xpected from the design principle, owing to the introductiono ft he 4-hydroxy-2,6-ditert-butylphenyl substituent at the bay position, three reversible one-electron waves with half-wave potentials of À0.55, À0.73, and À0.85 Vv ersusA g/AgCl wereo bserved in the CV pattern of 1,w hich are supposed to result from the formation of as ubstituted phenoxyl radical 1C,abiradical 1CC À with ap henoxyl radicala nd ac harge-delocalized radicala nion as well as ad ianion radical 1C 2À with ap henoxyl radical and ac harge-delocalized dianion. Although the reported first reduction potentials for common bay-unsubstituted PDIs to their charge-delocalizedr adicala nionP DIs are around À0.52 V, [15] which is slightly larger than those of phenols to phenoxyl radicals (À0.60 V), [16] in this case, the CÀCc oupling between the electron-donating 4-hydroxy-2,6-di-tert-butylphenyl substituent and the electron-withdrawing PDIsl eads to reversed reduction potentials between the phenol substituent andt he PDI skeleton. Accordingly,t he phenol substituent in 1 is first oxidized into its phenoxyl radicald uring the electrochemical reaction.…”

Design Strategies toward Enhancing the Performance of Organic Electrode Materials in Metal-Ion Batteries

“…N-type galvinoxyl and phenoxyl radicals were usually applied as the anode materials for aqueous/non-aqueous batteries. 25,26 Their capacities are lower than those of nitroxyl radicals because of the larger molecular weight of their units. Moreover, they suffer from low intrinsic conductivity and a self-discharge problem, which are the common challenges for organic radicals.…”