Water Contributes to Higher Energy Density and Cycling Stability of Prussian Blue Analogue Cathodes for Aqueous Sodium-Ion Batteries

In this work, we performed a comprehensive study of Prussian blue and its analogues (PBAs), one of the most promising cathode materials for aqueous sodium-ion batteries for large-scale energy-storage systems, using first-principles calculations. It is confirmed that dry PBAs generally undergo a phase transition from a rhombohedral Na2PR­(CN)6 (where P and R are transition metals) to a tetragonal/cubic PR­(CN)6 during Na extraction, in agreement with experimental observations. Using a grand potential phase diagram construction, we show that water and Na co-intercalation result in fundamentally different phase transition behavior and, hence, electrochemical voltage profiles in wet versus dry electrolytes. Lattice water increases the average voltage and reduces the volume change during electrochemical cycling, resulting in both higher energy density and better cycling stability. Finally, we identified four new PBA compositions, Na2CoMn­(CN)6, Na2NiMn­(CN)6, Na2CuMn­(CN)6, and Na2ZnMn­(CN)6, that show great promise as cathodes for aqueous rechargeable Na-ion batteries

Additional file 1 of Two putative calcium-dependent protein kinases are involved in the regulation of sugarcane defense genes

Additional file 1: Table S1. Sequences of primers used in this study

Elucidating the Limit of Li Insertion into the Spinel Li₄Ti₅O₁₂

In this work, we show that the well-known lithium-ion anode material, Li4Ti5O12, exhibits exceptionally high initial capacity of 310 mAh g–1 when it is discharged to 0.01 V. It maintains a reversible capacity of 230 mAh g–1, far exceeding the “theoretical” capacity of 175 mAh g–1 when this anode is lithiated to the composition Li7Ti5O12. Neutron diffraction analyses identify that additional Li reversibly enters into the Li7Ti5O12 to form Li8Ti5O12. density functional theory (DFT) calculations reveal the average potentials of the Li4Ti5O12 to Li7Ti5O12 step and the Li7Ti5O12 to Li8Ti5O12 step are 1.57 and 0.19 V, respectively, which are in excellent agreement with experimental results. Transmission electron microscopy (TEM) studies confirm that the irreversible capacity of Li4Ti5O12 during its first cycle originates from the formation of a solid electrolyte interface (SEI) layer. This work clarifies the fundamental lithiation mechanism of the Li4Ti5O12, when lithiated to 0.01 V vs Li

Elucidating the Limit of Li Insertion into the Spinel Li₄Ti₅O₁₂

In this work, we show that the well-known lithium-ion anode material, Li4Ti5O12, exhibits exceptionally high initial capacity of 310 mAh g–1 when it is discharged to 0.01 V. It maintains a reversible capacity of 230 mAh g–1, far exceeding the “theoretical” capacity of 175 mAh g–1 when this anode is lithiated to the composition Li7Ti5O12. Neutron diffraction analyses identify that additional Li reversibly enters into the Li7Ti5O12 to form Li8Ti5O12. density functional theory (DFT) calculations reveal the average potentials of the Li4Ti5O12 to Li7Ti5O12 step and the Li7Ti5O12 to Li8Ti5O12 step are 1.57 and 0.19 V, respectively, which are in excellent agreement with experimental results. Transmission electron microscopy (TEM) studies confirm that the irreversible capacity of Li4Ti5O12 during its first cycle originates from the formation of a solid electrolyte interface (SEI) layer. This work clarifies the fundamental lithiation mechanism of the Li4Ti5O12, when lithiated to 0.01 V vs Li

Elucidating the Limit of Li Insertion into the Spinel Li₄Ti₅O₁₂

In this work, we show that the well-known lithium-ion anode material, Li4Ti5O12, exhibits exceptionally high initial capacity of 310 mAh g–1 when it is discharged to 0.01 V. It maintains a reversible capacity of 230 mAh g–1, far exceeding the “theoretical” capacity of 175 mAh g–1 when this anode is lithiated to the composition Li7Ti5O12. Neutron diffraction analyses identify that additional Li reversibly enters into the Li7Ti5O12 to form Li8Ti5O12. density functional theory (DFT) calculations reveal the average potentials of the Li4Ti5O12 to Li7Ti5O12 step and the Li7Ti5O12 to Li8Ti5O12 step are 1.57 and 0.19 V, respectively, which are in excellent agreement with experimental results. Transmission electron microscopy (TEM) studies confirm that the irreversible capacity of Li4Ti5O12 during its first cycle originates from the formation of a solid electrolyte interface (SEI) layer. This work clarifies the fundamental lithiation mechanism of the Li4Ti5O12, when lithiated to 0.01 V vs Li

Elucidating the Limit of Li Insertion into the Spinel Li₄Ti₅O₁₂

In this work, we show that the well-known lithium-ion anode material, Li4Ti5O12, exhibits exceptionally high initial capacity of 310 mAh g–1 when it is discharged to 0.01 V. It maintains a reversible capacity of 230 mAh g–1, far exceeding the “theoretical” capacity of 175 mAh g–1 when this anode is lithiated to the composition Li7Ti5O12. Neutron diffraction analyses identify that additional Li reversibly enters into the Li7Ti5O12 to form Li8Ti5O12. density functional theory (DFT) calculations reveal the average potentials of the Li4Ti5O12 to Li7Ti5O12 step and the Li7Ti5O12 to Li8Ti5O12 step are 1.57 and 0.19 V, respectively, which are in excellent agreement with experimental results. Transmission electron microscopy (TEM) studies confirm that the irreversible capacity of Li4Ti5O12 during its first cycle originates from the formation of a solid electrolyte interface (SEI) layer. This work clarifies the fundamental lithiation mechanism of the Li4Ti5O12, when lithiated to 0.01 V vs Li

Two-Dimensional Graphitic Carbon Nitride for Improving the Performance of Organic Solar Cells

Organic solar cells (OSCs) have attracted lots of attention owing to their low cost, lightweight, and flexibility properties. Nowadays, the performance of OSCs is continuously improving with the development of active layer materials. However, the traditional hole transport layer (HTL) material Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) presents insufficient conductivity and rapid degradation, which decreases the efficiency and stability of OSCs. To conquer the challenge, the two-dimensional (2D) graphitic carbon nitride (g-C3N4) nanomaterials incorporated into the PEDOT:PSS as hybrid HTL are reported. The addition of g-C3N4 into PEDOT:PSS enables the thickness of the HTL to decrease for enhancing the transmittance of the film and increase the conductivity of PEDOT:PSS. Thus, the device exhibts improved charge transport and suppressed carrier recombination, leading to the increase in short-circuit current density and power conversion efficiency of the devices. This work demonstrates that the incorporation of 2D g-C3N4 into PEDOT:PSS for D18:Y6 and PM6:L8-BO-based OSCs can significantly improve the device efficiency to 17.48% and 18.47% with the enhancement of 7.04% and 8.46%, respectively