A new coordination polymer based on an aromatic carbonyl ligand is prepared and investigated as a positive active material for lithium ion batteries, namely, [Li2(C6H2O4)] (1). It is synthesized by the dehydration of [Li2(C6H2O4)·2H2O] (2). These compounds are characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), elemental analysis (EA), single crystal X-ray diffraction methods and powder X-ray diffraction (XRD). As positive material, compound 1 has an initial discharge capacity of 176 mAh·g−1 and a columbic efficiency of 93.18% in the first cycle. It might provide a new method for finding new positive-electrode materials in lithium ion batteries.

better organic active layer materials, such as those star materials of P3HT (2005 by Kim et al.), [2c] DR3TBDTT (2013 by Chen et al.), [2e] ITIC (2015 by Zhan et al.), [2f ] PM6 (2015 by Hou et al.), [2g] Y6 (2019 by Zou et al.), [2h] D18 (2018 by Ding et al.). [2i] Especially in 2019, the rapidly developing OSCs stepped into a new era of PCE exceeding 15% due to the emergence of a super-star acceptor Y6. [2g] As we all known that two determining factors for PCE of OSCs are the active layer materials and its morphology. Therefore, there have been main two approaches for higher performance, one is to get better molecules, and the latter one is to achieve better morphology. While we are always exploring more efficient active layer materials, the journey has been long and challenging. Therefore, it would be much easier to tune the morphology for better performance using some existing materials to achieve their best intrinsic performance. Up to now, tremendous efforts in tuning morphology have been made in the Y6 analogs-based OSCs, such as more suitable coating solvent, [3] solvent [4] or low boiling point solid additives, [5] post treatments of thermal or solvent annealing, [6] rendering the PCE over 18%. [7] In spite of the impressive PCE achieved, the continuously increasing performance of Y6 analogs-based OSCs indicates that the intrinsic best performance might not have been achieved.The above strategies of morphology regulation, such as more suitable coating solvent, solvent or low boiling point solid additives, post treatments of thermal or solvent annealing, can adapt a favorable morphology upon the quick solvent volatile process or post-treatment process by controlling the crystallization and phase separation process. In addition, a multicomponent strategy, which introduces a guest component into the host systems in OSCs, has been proved as an effective way to further improve the device performance recently. [7a,8] The application of a multicomponent strategy can break the limits of light absorption of the existing host systems, optimize the morphology and energy level alignment for the active layer, and thus improve the efficiency of OSC devices. Thus, a feasible multicomponent strategy based on a state-of-the-art system is expected to guide superior device performances. In the past decade, the numerous oligomer-like donors-based organic A wide bandgap oligomer-like donor CNS-6-8 is synthesized and incorporated into the host PM6:Y6:PC 71 BM system to tune the morphology of the active layer for better device performance. Due to the good miscibility of CNS-6-8 with both host donor (PM6) and acceptors (Y6 and PC 71 BM), an optimized morphology is achieved with the appropriate phase separation size and enhanced crystallinity, which ultimately leads to more efficient exciton dissociation, charge transport, and lower nonradiative energy loss. As a result, the quaternary device achieves an improved efficiency of 18.07%, with a simultaneously increased open circuit voltage of 0.868 V, fill factor of 78....

Guided by a semi-empirical model, two small-molecule acceptors were rationally designed and an impressive PCE of 15.05% was achieved.

The paper discusses the issues of heterogeneity and stability of cross-country growth regressions that have been used to study the problem of convergence. Almost all studies use pooled regressions. The paper considers the issue of pooling under heterogeneity using a hierarchical Bayesian method and estimates growth regressions for different panels studied in earlier papers, and different regimes. The conclusion is that the convergence rates are higher than those obtained from pooled regressions under the assumption of homogeneity and that there is instability over time in the relationships.