MnCO3 on Graphene Porous Framework via Diffusion-Driven Layer-by-Layer Assembly for High-Performance Pseudocapacitor

Insights into Nano- and Micro-Structured Scaffolds for Advanced Electrochemical Energy Storage

Adopting a nano- and micro-structuring approach to fully unleashing the genuine potential of electrode active material benefits in-depth understandings and research progress toward higher energy density electrochemical energy storage devices at all technology readiness levels. Due to various challenging issues, especially limited stability, nano- and micro-structured (NMS) electrodes undergo fast electrochemical performance degradation. The emerging NMS scaffold design is a pivotal aspect of many electrodes as it endows them with both robustness and electrochemical performance enhancement, even though it only occupies complementary and facilitating components for the main mechanism. However, extensive efforts are urgently needed toward optimizing the stereoscopic geometrical design of NMS scaffolds to minimize the volume ratio and maximize their functionality to fulfill the ever-increasing dependency and desire for energy power source supplies. This review will aim at highlighting these NMS scaffold design strategies, summarizing their corresponding strengths and challenges, and thereby outlining the potential solutions to resolve these challenges, design principles, and key perspectives for future research in this field. Therefore, this review will be one of the earliest reviews from this viewpoint.

Silk nanofibrils-MOF composite membranes for pollutant removal from water

Membrane separation technology is considered an effective strategy to remove pollutants in sewage. However, it remains a significant challenge to fabricate inexpensive membranes with high purification efficiency. Therefore, the present study proposes the integration of silk nanofibrils (SNFs) and polydopamine⊂metal-organic framework (PDA⊂MOF) nanoparticles to prepare self-supporting membranes, which can effectively intercept nanoparticle pollutants through the size exclusion effect and can strongly adsorb organic dyes and metal ions by SNF. In addition, PDA⊂MOF enables these membranes to adsorb small molecules and heavy metal ions during the filtration process, thereby effectively removing various pollutants from sewage. The integration of size-exclusion and adsorption capabilities enables the SNF/PDA⊂MOF membrane to remove nanoparticles, small-molecule dyes, heavy metal ions, and radioactive elements. This work provides a rational approach for the design and development of the next generation of water treatment membranes and is expected to be used in environmental, food-related, and biomedical fields.

Decorating MnO2 nanosheets on MOF-derived Co3O4 as a battery-type electrode for hybrid supercapacitors

Metal–organic framework-derived materials are now considered potential next-generation electrode materials for supercapacitors. In this present investigation, Co₃O₄@MnO₂ nanosheets are synthesized using ZIF-67, which is used as a sacrificial template through a facile hydrothermal method. The unique vertically grown nanosheets provide an effective pathway for rapidly transporting electrons and ions. As a result, the ZIF-67 derived Co₃O₄@MnO₂-3 electrode material shows a high specific capacitance of 768 C g⁻¹ at 1 A g⁻¹ current density with outstanding cycling stability (86% retention after 5000 cycles) and the porous structure of the material has a good BET surface area of 160.8 m² g⁻¹. As a hybrid supercapacitor, Co₃O₄@MnO₂-3//activated carbon exhibits a high specific capacitance (82.9 C g⁻¹) and long cycle life (85.5% retention after 5000 cycles). Moreover, a high energy density of 60.17 W h kg⁻¹ and power density of 2674.37 W kg⁻¹ has been achieved. This attractive performance reveals that Co₃O₄@MnO₂ nanosheets could find potential applications as an electrode material for high-performance hybrid supercapacitors.

Metal–organic framework-derived materials are now considered potential next-generation electrode materials for supercapacitors.

Phase transformation mechanism of MnCO3 as cathode materials for aqueous zinc-ion batteries

Aqueous rechargeable zinc-ion batteries (ZIBs) have been given more and more attention because of their high specific capacity, high safety, and low cost. The reasonable design of Mn-based cathode materials is an effective way to improve the performance of ZIBs. Herein, a square block MnCO₃ electrode material is synthesized on the surface of carbon cloth by a one-step hydrothermal method. The phase transition of MnCO₃ was accompanied by the continuous increase of specific capacity, and finally maintained good cycle stability in the charge–discharge process. The maximum specific capacity of MnCO₃ electrode material can reach 83.62 mAh g⁻¹ at 1 A g⁻¹. The retention rate of the capacity can reach 85.24% after 1,500 cycles compared with the stable capacity (the capacity is 61.44 mAh g⁻¹ under the 270th cycle). Ex situ characterization indicates that the initial MnCO₃ gradually transformed into MnO₂ accompanied by the embedding and stripping of H⁺ and Zn²⁺ in charge and discharge. When MnCO₃ is no longer transformed into MnO₂, the cycle tends to be stable. The phase transformation of MnCO₃ could provide a new research idea for improving the performance of electrode materials for energy devices.