@article{14733,
  abstract     = {Redox flow batteries (RFBs) rely on the development of cheap, highly soluble, and high-energy-density electrolytes. Several candidate quinones have already been investigated in the literature as two-electron anolytes or catholytes, benefiting from fast kinetics, high tunability, and low cost. Here, an investigation of nitrogen-rich fused heteroaromatic quinones was carried out to explore avenues for electrolyte development. These quinones were synthesized and screened by using electrochemical techniques. The most promising candidate, 4,8-dioxo-4,8-dihydrobenzo[1,2-d:4,5-d′]bis([1,2,3]triazole)-1,5-diide (−0.68 V(SHE)), was tested in both an asymmetric and symmetric full-cell setup resulting in capacity fade rates of 0.35% per cycle and 0.0124% per cycle, respectively. In situ ultraviolet-visible spectroscopy (UV–Vis), nuclear magnetic resonance (NMR), and electron paramagnetic resonance (EPR) spectroscopies were used to investigate the electrochemical stability of the charged species during operation. UV–Vis spectroscopy, supported by density functional theory (DFT) modeling, reaffirmed that the two-step charging mechanism observed during battery operation consisted of two, single-electron transfers. The radical concentration during battery operation and the degree of delocalization of the unpaired electron were quantified with NMR and EPR spectroscopy.},
  author       = {Jethwa, Rajesh B and Hey, Dominic and Kerber, Rachel N. and Bond, Andrew D. and Wright, Dominic S. and Grey, Clare P.},
  issn         = {2574-0962},
  journal      = {ACS Applied Energy Materials},
  keywords     = {Electrical and Electronic Engineering, Materials Chemistry, Electrochemistry, Energy Engineering and Power Technology, Chemical Engineering (miscellaneous)},
  number       = {2},
  pages        = {414--426},
  publisher    = {American Chemical Society},
  title        = {{Exploring the landscape of heterocyclic quinones for redox flow batteries}},
  doi          = {10.1021/acsaem.3c02223},
  volume       = {7},
  year         = {2024},
}

@article{14687,
  abstract     = {The short history of research on Li-O2 batteries has seen a remarkable number of mechanistic U-turns over the years. From the initial use of carbonate electrolytes, that were then found to be entirely unsuitable, to the belief that (su)peroxide was solely responsible for degradation, before the more reactive singlet oxygen was found to form, to the hypothesis that capacity depends on a competing surface/solution mechanism before a practically exclusive solution mechanism was identified. Herein, we argue for an ever-fresh look at the reported data without bias towards supposedly established explanations. We explain how the latest findings on rate and capacity limits, as well as the origin of side reactions, are connected via the disproportionation (DISP) step in the (dis)charge mechanism. Therefrom, directions emerge for the design of electrolytes and mediators on how to suppress side reactions and to enable high rate and high reversible capacity.},
  author       = {Jethwa, Rajesh B and Mondal, Soumyadip and Pant, Bhargavi and Freunberger, Stefan Alexander},
  issn         = {1521-3773},
  journal      = {Angewandte Chemie International Edition},
  keywords     = {General Chemistry, Catalysis},
  number       = {28},
  publisher    = {Wiley},
  title        = {{To DISP or not? The far‐reaching reaction mechanisms underpinning Lithium‐air batteries}},
  doi          = {10.1002/anie.202316476},
  volume       = {63},
  year         = {2024},
}

@article{13044,
  abstract     = {Singlet oxygen (1O2) formation is now recognised as a key aspect of non-aqueous oxygen redox chemistry. For identifying 1O2, chemical trapping via 9,10-dimethylanthracene (DMA) to form the endoperoxide (DMA-O2) has become the mainstay method due to its sensitivity, selectivity, and ease of use. While DMA has been shown to be selective for 1O2, rather than forming DMA-O2 with a wide variety of potentially reactive O-containing species, false positives might hypothetically be obtained in the presence of previously overlooked species. Here, we first give unequivocal direct spectroscopic proof by the 1O2-specific near infrared (NIR) emission at 1270 nm for the previously proposed 1O2 formation pathways, which centre around superoxide disproportionation. We then show that peroxocarbonates, common intermediates in metal-O2 and metal carbonate electrochemistry, do not produce false-positive DMA-O2. Moreover, we identify a previously unreported 1O2-forming pathway through the reaction of CO2 with superoxide. Overall, we give unequivocal proof for 1O2 formation in non-aqueous oxygen redox and show that chemical trapping with DMA is a reliable method to assess 1O2 formation.},
  author       = {Mondal, Soumyadip and Jethwa, Rajesh B and Pant, Bhargavi and Hauschild, Robert and Freunberger, Stefan Alexander},
  issn         = {1364-5498},
  journal      = {Faraday Discussions},
  keywords     = {Physical and Theoretical Chemistry},
  pages        = {175--189},
  publisher    = {Royal Society of Chemistry},
  title        = {{Singlet oxygen in non-aqueous oxygen redox: Direct spectroscopic evidence for formation pathways and reliability of chemical probes}},
  doi          = {10.1039/d3fd00088e},
  volume       = {248},
  year         = {2024},
}

@article{12737,
  abstract     = {The substitution of heavier, more metallic atoms into classical organic ligand frameworks provides an important strategy for tuning ligand properties, such as ligand bite and donor character, and is the basis for the emerging area of main-group supramolecular chemistry. In this paper, we explore two new ligands [E(2-Me-8-qy)3] [E = Sb (1), Bi (2); qy = quinolyl], allowing a fundamental comparison of their coordination behavior with classical tris(2-pyridyl) ligands of the type [E′(2-py)3] (E = a range of bridgehead atoms and groups, py = pyridyl). A range of new coordination modes to Cu+, Ag+, and Au+ is seen for 1 and 2, in the absence of steric constraints at the bridgehead and with their more remote N-donor atoms. A particular feature is the adaptive nature of these new ligands, with the ability to adjust coordination mode in response to the hard–soft character of coordinated metal ions, influenced also by the character of the bridgehead atom (Sb or Bi). These features can be seen in a comparison between [Cu2{Sb(2-Me-8-qy)3}2](PF6)2 (1·CuPF6) and [Cu{Bi(2-Me-8-qy)3}](PF6) (2·CuPF6), the first containing a dimeric cation in which 1 adopts an unprecedented intramolecular N,N,Sb-coordination mode while in the second, 2 adopts an unusual N,N,(π-)C coordination mode. In contrast, the previously reported analogous ligands [E(6-Me-2-py)3] (E = Sb, Bi; 2-py = 2-pyridyl) show a tris-chelating mode in their complexes with CuPF6, which is typical for the extensive tris(2-pyridyl) family with a range of metals. The greater polarity of the Bi–C bond in 2 results in ligand transfer reactions with Au(I). Although this reactivity is not in itself unusual, the characterization of several products by single-crystal X-ray diffraction provides snapshots of the ligand transfer reaction involved, with one of the products (the bimetallic complex [(BiCl){ClAu2(2-Me-8-qy)3}] (8)) containing a Au2Bi core in which the shortest Au → Bi donor–acceptor bond to date is observed.},
  author       = {García-Romero, Álvaro and Waters, Jessica E. and Jethwa, Rajesh B and Bond, Andrew D. and Colebatch, Annie L. and García-Rodríguez, Raúl and Wright, Dominic S.},
  issn         = {1520-510X},
  journal      = {Inorganic Chemistry},
  number       = {11},
  pages        = {4625--4636},
  publisher    = {American Chemical Society},
  title        = {{Highly adaptive nature of group 15 tris(quinolyl) ligands─studies with coinage metals}},
  doi          = {10.1021/acs.inorgchem.3c00057},
  volume       = {62},
  year         = {2023},
}

@article{13041,
  abstract     = {A series of triarylamines was synthesised and screened for their suitability as catholytes in redox flow batteries using cyclic voltammetry (CV). Tris(4-aminophenyl)amine was found to be the strongest candidate. Solubility and initial electrochemical performance were promising; however, polymerisation was observed during electrochemical cycling leading to rapid capacity fade prescribed to a loss of accessible active material and the limitation of ion transport processes within the cell. A mixed electrolyte system of H3PO4 and HCl was found to inhibit polymerisation producing oligomers that consumed less active material reducing rates of degradation in the redox flow battery. Under these conditions Coulombic efficiency improved by over 4 %, the maximum number of cycles more than quadrupled and an additional theoretical capacity of 20 % was accessed. This paper is, to our knowledge, the first example of triarylamines as catholytes in all-aqueous redox flow batteries and emphasises the impact supporting electrolytes can have on electrochemical performance.},
  author       = {Farag, Nadia L. and Jethwa, Rajesh B and Beardmore, Alice E. and Insinna, Teresa and O'Keefe, Christopher A. and Klusener, Peter A.A. and Grey, Clare P. and Wright, Dominic S.},
  issn         = {1864-564X},
  journal      = {ChemSusChem},
  number       = {13},
  publisher    = {Wiley},
  title        = {{Triarylamines as catholytes in aqueous organic redox flow batteries}},
  doi          = {10.1002/cssc.202300128},
  volume       = {16},
  year         = {2023},
}