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Herein, two novel copolymers of dihydrophenazine with diphenylamine (PDPAPZ) and phenothiazine (PPTZPZ) are synthesized and investigated as cathode materials for dual‐ion batteries. Both polymers demonstrate high average discharge potentials (3.5–3.6 V) in lithium cells. The PDPAPZ//Li cells demonstrate impressive rate capability: specific capacities of 101 and 82 mAh g−1 are reached under galvanostatic charging and discharging at the high current densities of 5 and 20 A g−1, respectively. The capacity retention of 86% and 34% after 100 and 25 000 cycles, respectively, features decent operational stability of the batteries. Furthermore, an encouraging energy density of 398 Wh kg−1 is achieved in potassium PDPAPZ//K cells. The obtained values place PDPAPZ on par with the best organic cathode materials for fast lithium and potassium batteries.

The structure of MQ copolymers of the general chemical formula [(CH3)3SiO0.5]m [SiO2]n was characterized by means of solid-state magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The MQ copolymers are highly branched polycyclic compounds (densely cross-linked nanosized networks). MQ copolymers were prepared by hydrolytic polycondensation in active medium. 29Si NMR spectra were obtained by single pulse excitation (or direct polarization, DP) and cross-polarization (CP) 29Si{1H} techniques in concert with MAS. It was shown that material consist of monofunctional M (≡SiO Si (CH3)3) and two types of tetrafunctional Q units: Q4 ((≡SiO)4Si) and Q3 ((≡SiO)3SiOH). Spin–lattice relaxation times T1 measurements of 29Si nuclei and analysis of 29Si{1H} variable contact time signal intensities allowed us to obtain quantitative data on the relative content of different sites in copolymers. These investigations indicate that MQ copolymers represent dense structure with core and shell.

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