Facile Solid-State Synthesis to In Situ Generate a Composite Coating Layer Composed of Spinel-Structural Compounds and Li3PO4 for Stable Cycling of LiCoO2 at 4.6 V

Due to its high energy density, high-voltage LiCoO2 is the preferred cathode material for consumer electronic products. However, its commercial viability is hindered by rapid capacity decay resulting from structural degradation and surface passivation during cycling at 4.6 V. The key to achieving stable cycling of LiCoO2 at high voltages lies in constructing a highly stable interface to mitigate surface side reactions. In this study, we present a facile in situ coating strategy that is amenable to mass production through a simple wet-mixing process, followed by high-temperature calcination. By capitalizing on the facile dispersion characteristics of nano-TiO2 in ethanol and the ethanol dissolubility of LiPO2F2, we construct a uniform precoating layer on LiCoO2 with nano-TiO2 and LiPO2F2. The subsequent thermal treatment triggers an in situ reaction between the coating reagents and LiCoO2, yielding a uniform composite coating layer. This composite layer comprises spinel-structured compounds (e.g., LiCoTiO4) and Li3PO4, which exhibit excellent chemical and structural stability under high-voltage conditions. The uniform and stable coating layer effectively prevents direct contact between LiCoO2 and the electrolyte, thereby reducing side reactions and suppressing the surface passivation of LiCoO2 particles. As a result, coated LiCoO2 maintains favorable electronic and ionic conductivity even after prolonged cycling. The synergistic effects of spinel-structured compounds and Li3PO4 contribute to the superior performance of LiCoO2, demonstrating a high capacity of 202.1 mA h g-1 (3.0-4.6 V, 0.5 C, 1 C = 274 mA g-1), with a capacity retention rate of 96.7% after 100 cycles.

Effective and Low-Cost In Situ Surface Engineering Strategy to Enhance the Interface Stability of an Ultrahigh Ni-Rich NCMA Cathode

Ultrahigh Ni-rich quaternary layered oxides LiNi_1-x-y-zCo_xMn_yAl_zO₂ (1 - x - y - z ≥ 0.9) are regarded as some of the most promising cathode candidates for lithium-ion batteries (LIBs) because of their high energy density and low cost. However, poor rate capacity and cycling performance severely limit their further commercial applications. Herein, an in situ coating strategy is developed to construct a uniform LiAlO₂ layer. The NH₄HCO₃ solution is added to a NaAlO₂ solution to form a weak alkaline condition, which can reduce the hydrolysis rate of NaAlO₂, thus enabling uniform deposition of Al(OH)₃ on the surface of a Ni_0.9Co_0.07Mn_0.01Al_0.02(OH)₂ (NCMA) precursor. The LiAlO₂-coated samples show enhanced cycling stability and rate capacity. The capacity retention of NCMA increases from 70.7% to 88.3% after 100 cycles at 1 C with an optimized LiAlO₂ coating amount of 3 wt %. Moreover, the 3 wt % LiAlO₂-coated sample also delivers a better rate capacity of 162 mAh g^-1 at 5 C, while that of an uncoated sample is only 144 mAh g^-1. Such a large improvement of the electrochemical performance should be attributed to the fact that a uniform LiAlO₂ coating relieves harmful interfacial parasitic reactions and stabilizes the interface structure. Therefore, this in situ coating approach is a viable idea for the design of higher-energy-density cathode materials.

Face-lifting the surface of LiNi0.8Co0.15Al0.05O2cathode via Y(PO3)3to form anin situtriple composite Li-ion conductor coating layer with the enhanced electrochemical performance

Due to the assets such as adequate discharge capacity and rational cost, LiNi_0.8Co_0.15Al_0.05O₂(NCA), a high-nickel ternary layered oxide, is regarded to be a favorable cathode contender for lithium-ion batteries. However, the superior commercial application is restricted by the surface residual alkaline lithium salt (LiOH or/and Li₂CO₃) of nickel-rich cathode materials, which will expedite the disintegration of the structure and the engendering of gas (CO₂). Therefore, in this paper, we devise and fabricate a Y(PO₃)₃modified LiNi_0.8Co_0.15Al_0.05O₂(NCA), intending to optimize the surface residual alkaline lithium salt (antecedent deportation of H₂O and CO₂) while forming anin situtriple composite Li-ion conductor coating (Y(PO₃)₃-Li₃PO₄-YPO₄) to enhance the electrochemical behavior. Under this method, the 2 mol% Y(PO₃)₃modified NCA electrode reveals exceptional rate capability (5 C/156.3 mAh g^-1) and extraordinary cycle stability after 200 cycles (2 C/88.3%), whereas the original sample is only 5 C/123.1 mAh g^-1and 2 C/71.2% after 200 cycles. Conspicuously, even under the draconian circumstances of the high temperature and the high rate at 55 °C/1 C, the 2 mol% Y(PO₃)₃modified NCA electrode sustains a high reversible capacity, with an admirable capacity retention rate of 89.4% after 100 cycles. These contented results signify that the surface remodeling tactic presents a viable scheme for ameliorating high-nickel materials' performance and appropriateness.

In situ polyaniline coating of Prussian blue as cathode material for sodium-ion battery

Prussian blue (PB) has great potential for use as a sodium cathode material owing to its high working potential and cube frame structure. Herein, this work reports a two-step method to synthesize PB with ascorbic acid as the ball-milling additive, which improves the electrochemical rate performance of PB during the traditional co-precipitation method. The obtained PB sample exhibited a superior specific capability (113.3 mAh g-1 even at 20 C, 1 C = 170 mA g-1) and a specific capacity retention of 84.8% after 100 cycles at 1 C rate. In order to enhance the cycling performance of the PB, an in situ polyaniline coating strategy was employed in which aniline was added into the electrolyte and polymerized under electrochemical conditions. The coated anode exhibited a high specific capacity retention of 62.7% after 500 cycles, which is significantly higher than that of the non-coated sample, which only remains 40.1% after 500 cycles. This development has shown a great potential as a low-cost, high-performance and environment-friendly technology for large-scale industrial application of PB.

In Situ Coating CsPbBr3 Nanocrystals with Graphdiyne to Boost the Activity and Stability of Photocatalytic CO2 Reduction

The instability and low inferior catalytic activity of metal-halide perovskite nanocrystals are crucial issues for promoting their practical application in the photocatalytic field. Herein, we in situ coat a thin graphdiyne (GDY) layer on CsPbBr₃ nanocrystals based on a facile microwave synthesis method, and employ it as a photocatalyst for CO₂ reduction. Under the protection of GDY, the CsPbBr₃-based photocatalyst delivers significantly improved stability in a photocatalytic system containing water concomitant with enhanced CO₂ uptake capacity. The favorable energy offset and close contact between CsPbBr₃ and GDY trigger swift photogenerated electron transfer from CsPbBr₃ to doping metal sites in GDY, boosting a remarkable improvement in the photocatalytic performance for CO₂ reduction. Without adding traditional sacrificial reductants, the cobalt-doped photocatalyst achieves a high yield of 27.7 μmol g^-1 h^-1 for photocatalytic CO₂ conversion to CO based on water as a desirable electron source, which is about 8 times higher than that of pristine CsPbBr₃ nanocrystals.

Investigation on the Electrochemical Properties and Stabilized Surface/Interface of Nano-AlPO4-Coated Li1.15Ni0.17Co0.11Mn0.57O2 as the Cathode for Lithium-Ion Batteries

Being considered as one of the most potential cathode materials, Li_1.15Ni_0.17Co_0.11Mn_0.57O₂ draws plenty of attention towards its optimization on cycling and rate performance. The surface coating process provides a longer cycling life and better rate performance for the cathodes. A systematic investigation has been carried out on the nano-AlPO₄ coating layer for the Li_1.15Ni_0.17Co_0.11Mn_0.57O₂ cathode material through a facile in situ dispersion process. The 1% coated cathode material can hold about 90% capacity retention after 100 cycles. Besides, the surface coating enhances the rate ability of Li_1.15Ni_0.17Co_0.11Mn_0.57O₂, which holds a reversible capacity of 202.3 mAh g^-1 at the rate of 1C. Surface information is collected during cycling, which reveals that less side reactions occur on the electrode-electrolyte interface after the coating process for improved cycling and rate performance.

New Aspects in the Formulation of Drugs Based on Three Case Studies

The improvement of pharmaceutical dosage forms, such as tablets, towards drug delivery control and cost efficiency is of great importance in formulation technologies. Here, three examples: in situ coating, freeze casting and protein-based biocomposites are presented that address the above mentioned issues and contribute to further developments in formulation technologies. The in situ coating increases the economic efficiency by saving process steps in comparison to a conventional tableting process and provides a crystalline coating for a tailorable drug delivery rate. The freeze casting allows the control over the surface area of a drug delivery system (DDS) by providing different numbers and sizes of pores, which in conjunction with adequate additives offer an efficient instrument for drug delivery control, especially by accelerating the dissolution effect. Protein-based biocomposites are attractive materials for biomedical and pharmaceutical applications that can be applied as a polymeric DDS. They inherently combine degradability in vivo and in vitro, show a good biocompatibility, offer sites of adhesion for cells and may additionally be used to release embedded bioactive molecules. Here, a new approach regarding the incorporation of crystalline active pharmaceutical ingredients (API) into a protein matrix in one process step is presented. All three presented techniques mark decisive progress towards tailor-made drug delivery systems with respect to function, economic efficiency and the generation of additional values.