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Fluid‐rock dissolution occurs ubiquitously in geological systems. Surface‐volume scaling is central to predicting overall dissolution rate R involved in modeling dissolution processes. Previous works focused on single‐phase environments but overlooked the multiphase‐flow effect. Here, through limestone‐based microfluidics experiments, we establish a fundamental link between dissolution regimes and scaling laws. In regime I (uniform), the scaling is consistent with classic law, and a satisfactory prediction of R can be obtained. However, the scaling for regime II (localized) deviates significantly from classic law. The underlying mechanism is that the reaction‐induced gas phase forms a layer, acting as a barrier that hinders contact between the acid and rock. Consequently, the error between measurement and prediction continuously amplifies as dissolution proceeds; the predictability is poor. We propose a theoretical model that describes the regime transition, exhibiting excellent agreement with experimental results. This work offers guidance on the usage of scaling law in multiphase flow environments. Plain Language Summary Fluid‐rock dissolution is ubiquitous in natural and engineered systems, including karst formation, geological carbon sequestration, and acid stimulation. Recent developed method for CO2 sequestration relies on mineralization, which transforms CO2 into carbonate minerals through geochemical reactions involving dissolution. The precise modeling of dissolution processes at the continuum‐scale is dependent on the estimation of the overall dissolution rate using surface‐volume scaling laws. This important scaling law is always established in a single‐phase system. Here, through limestone‐based microfluidics experiments, we find that the scaling is significantly affected by the dissolution regime in a multiphase flow environment. When the injection rate is lower, and the geometry is more homogeneous, the dissolution regime adheres to classic law. On the other hand, when the flow is stronger and the heterogeneity exhibits, the dissolution scaling significantly diverges. Our discovery indicates that a layer of CO2 gas attaches to the uneven surface, causing a shielding effect on the dissolution and resulting in a notable deviation. Through establishing a theoretical model for the regime transition, this work offers guidance on the usage of scaling law across various dissolution scenarios. The newly developed scaling can enhance dissolution modeling precision in multiphase flow‐dissolution systems such as geologic carbon sequestration. Key Points We observe two regimes, and the scaling in regime II deviates significantly from classic law, with a poor predictability of dissolution rate We identify a barrier effect in real rock samples that inhibits the contact of acid and rock for the deviation of scaling in regime II We propose a theoretical model for regime transition that offers guidance on the usage of scaling law in multiphase environments

Reactive flow through geological fractures under stress is fundamental to subsurface hydrology. In this flow‐stress‐dissolution system, free‐surface dissolution within voids increases permeability, whereas pressure dissolution at contacting asperities combined with mechanical deformation seals the fracture. The interplay between these mechanisms controlling fracture sealing or opening remains to be explored. Here, we integrate numerical simulations with theoretical analysis to examine the coupled mechanical‐chemical processes. We develop a flow‐stress‐dissolution modeling approach with the incorporation of pressure dissolution, free‐surface dissolution and mechanical deformation for fractures in homogeneous mineral systems. Comparison with previously experiments demonstrates the ability of this approach and highlights the significant role of pressure dissolution for fracture sealing. Through extensive simulations with a wide range of flow rates, reaction rates and normal stresses, we find that stress induced‐mechanical compaction enhances the positive feedback mechanisms between free‐surface dissolution and solute transport, promoting the development of dissolution channels. Our analysis of permeability evolution under various stresses and dissolution patterns reveals that fracture sealing can occur in uniform and compact patterns depending on stress, whereas fracture opening spontaneously occurs in wormholes. Through theoretical analysis of the interplay between pressure dissolution and free‐surface dissolution, we propose a theoretical model for the occurrence of fracture sealing. A generalized phase diagram is then established that can effectively describe fracture sealing under varying flow rates, reaction rates, and normal stress conditions. Our work provides a foundation for assessing fracture leakage risks in subsurface engineering and holds practical implications for geological carbon and hydrogen storage.

Historically long accepted to be the singular root cause of capacity fading, transition metal dissolution has been reported to severely degrade the anode. However, its impact on the cathode behavior remains poorly understood. Here we show the correlation between capacity fading and phase/surface stability of an LiMn 2 O 4 cathode. It is revealed that a combination of structural transformation and transition metal dissolution dominates the cathode capacity fading. LiMn 2 O 4 exhibits irreversible phase transitions driven by manganese(III) disproportionation and Jahn-Teller distortion, which in conjunction with particle cracks results in serious manganese dissolution. Meanwhile, fast manganese dissolution in turn triggers irreversible structural evolution, and as such, forms a detrimental cycle constantly consuming active cathode components. Furthermore, lithium-rich LiMn 2 O 4 with lithium/manganese disorder and surface reconstruction could effectively suppress the irreversible phase transition and manganese dissolution. These findings close the loop of understanding capacity fading mechanisms and allow for development of longer life batteries. To unlock the potential of Mn-based cathode materials, the fast capacity fading process has to be first understood. Here the authors utilize advanced characterization techniques to look at a spinel LiMn 2 O 4 system, revealing that a combination of irreversible structural transformations and Mn dissolution takes responsibility.

Transition metal dissolution in cathode active material for Li-based batteries is a critical aspect that limits the cycle life of these devices. Although several approaches have been proposed to tackle this issue, this detrimental process is not yet overcome. Here, benefitting from the knowledge developed in the semiconductor research field, we apply an epitaxial method to construct an atomic wetting layer of LaTMO 3 (TM = Ni, Mn) on a LiNi 0.5 Mn 1.5 O 4 cathode material. Experimental measurements and theoretical analyses confirm a Stranski–Krastanov growth, where the strained wetting layer forms under thermodynamic equilibrium, and it is self-limited to monoatomic thickness due to the competition between the surface energy and the elastic energy. Being atomically thin and crystallographically connected to the spinel host lattices, the LaTMO 3 wetting layer offers long-term suppression of the transition metal dissolution from the cathode without impacting its dynamics. As a result, the epitaxially-engineered cathode material enables improved cycling stability (a capacity retention of about 77% after 1000 cycles at 290 mA g −1 ) when tested in combination with a graphitic carbon anode and a LiPF 6 -based non-aqueous electrolyte solution. Transition metal dissolution from cathode materials limits the cycle life of Li-ion batteries. Here, the authors report an atomic-thin protecting layer on the surface of a high-voltage cathode material, enabling long-term Li-ion battery cycling.

HighlightsThe Zn/MnO2 cell with inorganic colloidal electrolyte demonstrates unprecedented durability over 1000 cycles.For the cathode, the presence of the protective film can inhibit the dissolution of manganese element and the formation of irreversible by-products.For the anode, it can reduce the corrosion and de-solvation energy, inhibit the growth of dendrite and irreversible by-products.Zinc-ion batteries (ZIBs) is a promising electrical energy storage candidate due to its eco-friendliness, low cost, and intrinsic safety, but on the cathode the element dissolution and the formation of irreversible products, and on the anode the growth of dendrite as well as irreversible products hinder its practical application. Herein, we propose a new type of the inorganic highly concentrated colloidal electrolytes (HCCE) for ZIBs promoting simultaneous robust protection of both cathode/anode leading to an effective suppression of element dissolution, dendrite, and irreversible products growth. The new HCCE has high Zn2+ ion transference number (0.64) endowed by the limitation of SO42−, the competitive ion conductivity (1.1 × 10–2 S cm−1) and Zn2+ ion diffusion enabled by the uniform pore distribution (3.6 nm) and the limited free water. The Zn/HCCE/α-MnO2 cells exhibit high durability under both high and low current densities, which is almost 100% capacity retention at 200 mA g−1 after 400 cycles (290 mAh g−1) and 89% capacity retention under 500 mA g−1 after 1000 cycles (212 mAh g−1). Considering material sustainability and batteries’ high performances, the colloidal electrolyte may provide a feasible substitute beyond the liquid and all-solid-state electrolyte of ZIBs.

Two major challenges hinder the advance of aqueous zinc metal batteries for sustainable stationary storage: (1) achieving predominant Zn-ion (de)intercalation at the oxide cathode by suppressing adventitious proton co-intercalation and dissolution, and (2) simultaneously overcoming Zn dendrite growth at the anode that triggers parasitic electrolyte reactions. Here, we reveal the competition between Zn 2+ vs proton intercalation chemistry of a typical oxide cathode using ex-situ/ operando techniques, and alleviate side reactions by developing a cost-effective and non-flammable hybrid eutectic electrolyte. A fully hydrated Zn 2+ solvation structure facilitates fast charge transfer at the solid/electrolyte interface, enabling dendrite-free Zn plating/stripping with a remarkably high average coulombic efficiency of 99.8% at commercially relevant areal capacities of 4 mAh cm −2 and function up to 1600 h at 8 mAh cm −2 . By concurrently stabilizing Zn redox at both electrodes, we achieve a new benchmark in Zn-ion battery performance of 4 mAh cm −2 anode-free cells that retain 85% capacity over 100 cycles at 25 °C. Using this eutectic-design electrolyte, Zn | |Iodine full cells are further realized with 86% capacity retention over 2500 cycles. The approach represents a new avenue for long-duration energy storage. Achieving high-performance aqueous Zn-metal batteries is a challenge. Here, authors report a eutectic electrolyte that concurrently enables selective Zn 2+ intercalation at the cathode and highly reversible Zn metal plating/stripping, resulting in a benchmark high-areal capacity Zn anode-free cell.

Oxcarbazepine is one of the newer antiepileptic drugs and low aqueous solubility of Oxcarbazepine is responsible for its poor dissolution and delayed onset of action. The purpose of the present investigation is to increase the dissolution rate of Oxcarbazepine by preparing its solid dispersions with PEG 6000 using melting technique and subjecting the prepared solid dispersions to drug-carrier interaction, dissolution and stability studies and it was found that the dissolution rate was improved for Oxcarbazepine in its solid dispersion. As indicated from XRD and DSC studies, Oxcarbazepine was in the amorphous form in the solid dispersions, which confirmed the better dissolution rate of prepared stable solid dispersions. Pharmacokinetic profiles of Oxcarbazepine and solid dispersion were compared by one way ANOVA followed by a Dunnett Post Hoc test which indicated higher attainable plasma concentrations. Solid dispersion showed a difference with the pure drug in its pharmacokinetic profile which may be attributed to better dissolution rate of Oxcarbazepine from its solid dispersion.

The application of sodium-based batteries in grid-scale energy storage requires electrode materials that facilitate fast and stable charge storage at various temperatures. However, this goal is not entirely achievable in the case of P2-type layered transition-metal oxides because of the sluggish kinetics and unfavorable electrode|electrolyte interphase formation. To circumvent these issues, we propose a P2-type Na 0.78 Ni 0.31 Mn 0.67 Nb 0.02 O 2 (P2-NaMNNb) cathode active material where the niobium doping enables reduction in the electronic band gap and ionic diffusion energy barrier while favoring the Na-ion mobility. Via physicochemical characterizations and theoretical calculations, we demonstrate that the niobium induces atomic scale surface reorganization, hindering metal dissolution from the cathode into the electrolyte. We also report the testing of the cathode material in coin cell configuration using Na metal or hard carbon as anode active materials and ether-based electrolyte solutions. Interestingly, the Na||P2-NaMNNb cell can be cycled up to 9.2 A g −1 (50 C), showing a discharge capacity of approximately 65 mAh g −1 at 25 °C. Furthermore, the Na||P2-NaMNNb cell can also be charged/discharged for 1800 cycles at 368 mA g −1 and −40 °C, demonstrating a capacity retention of approximately 76% and a final discharge capacity of approximately 70 mAh g −1 . The practical application of sodium-ion batteries at subzero temperatures is hindered by the slow Na-ion transfer kinetics. Here, the authors reported the niobium doping of P2-type cathode active material capable of efficient battery cycling at low temperatures such as −40 °C.

The long-standing issue of lithium dendrite growth during repeated deposition or dissolution processes hinders the practical use of lithium-metal anodes for high-energy density batteries. Here, we demonstrate a promising lithiophilic–lithiophobic gradient interfacial layer strategy in which the bottom lithiophilic zinc oxide/carbon nanotube sublayer tightly anchors the whole layer onto the lithium foil, facilitating the formation of a stable solid electrolyte interphase, and prevents the formation of an intermediate mossy lithium corrosion layer. Together with the top lithiophobic carbon nanotube sublayer, this gradient interfacial layer can effectively suppress dendrite growth and ensure ultralong-term stable lithium stripping/plating. This strategy is further demonstrated to provide substantially improved cycle performance in copper current collector, 10 cm 2 pouch cell and lithium–sulfur batteries, which, coupled with a simple fabrication process and wide applicability in various materials for lithium-metal protection, makes the lithiophilic–lithiophobic gradient interfacial layer a favored strategy for next-generation lithium-metal batteries. Lithium metal batteries suffer from the dendrite growth upon electrochemical cycling. Here the authors introduce a lithiophilic-lithiophobic gradient interfacial ZnO/CNT layer, which facilitates the formation of a stable solid electrolyte interphase, and suppresses the growth of lithium dendrite.

A drug dissolution profile is one of the most critical dosage form characteristics with immediate and controlled drug release. Comparing the dissolution profiles of different pharmaceutical products plays a key role before starting the bioequivalence or stability studies. General recommendations for dissolution profile comparison are mentioned by the EMA and FDA guidelines. However, neither the EMA nor the FDA provides unambiguous instructions for comparing the dissolution curves, except for calculating the similarity factor f2. In agreement with the EMA and FDA strategy for comparing the dissolution profiles, this manuscript provides an overview of suitable statistical methods (CI derivation for f2 based on bootstrap, CI derivation for the difference between reference and test samples, Mahalanobis distance, model-dependent approach and maximum deviation method), their procedures and limitations. However, usage of statistical approaches for the above-described methods can be met with difficulties, especially when combined with the requirement of practice for robust and straightforward techniques for data evaluation. Therefore, the bootstrap to derive the CI for f2 or CI derivation for the difference between reference and test samples was selected as the method of choice.