Benefiting from a higher volumetric capacity (3833 mA h cm
−3
for Mg
vs.
2046 mA h cm
−3
for Li) and dendrite-free Mg metal anode, reversible Mg batteries (RMBs) are a promising chemistry for ...applications beyond Li ion batteries. However, RMBs are still severely restricted by the absence of high performance cathodes for any practical application. In this review, we provide a critical and rigorous review of Mg battery cathode materials, mainly reported since 2013, focusing on the impact of structure and composition on magnesiation kinetics. We discuss cathode materials, including intercalation compounds, conversion materials (O
2
, S, organic compounds), water co-intercalation cathodes (V
2
O
5
, MnO
2
etc.
), as well as hybrid systems using Mg metal anode. Among them, intercalation cathodes are further categorized by 3D (Chevrel phase, spinel structure
etc.
), 2D (layered structure), and 1D materials (polyanion: phosphate and silicate), according to the diffusion pathway of Mg
2+
in the framework. Instead of discussing every published work in detail, this review selects the most representative works and highlights the merits and challenges of each class of cathodes. Advances in theoretical analysis are also reviewed and compared with experimental results. This critical review will provide comprehensive knowledge of Mg cathodes and guidelines for exploring new cathodes for rechargeable magnesium batteries.
This paper provides a critical and rigorous review on Mg battery cathodes, focusing on the impact of structure and composition on magnesiation kinetics.
All‐solid‐state lithium batteries (ASSLBs) are considered as the next generation electrochemical energy storage devices because of their high safety and energy density, simple packaging, and wide ...operable temperature range. The critical component in ASSLBs is the solid‐state electrolyte. Among all solid‐state electrolytes, the sulfide electrolytes have the highest ionic conductivity and favorable interface compatibility with sulfur‐based cathodes. The ionic conductivity of sulfide electrolytes is comparable with or even higher than that of the commercial organic liquid electrolytes. However, several critical challenges for sulfide electrolytes still remain to be solved, including their narrow electrochemical stability window, the unstable interface between the electrolyte and the electrodes, as well as lithium dendrite formation in the electrolytes. Herein, the emerging sulfide electrolytes and preparation methods are reviewed. In particular, the required properties of the sulfide electrolytes, such as the electrochemical stabilities of the electrolytes and the compatible electrode/electrolyte interfaces are highlighted. The opportunities for sulfide‐based ASSLBs are also discussed.
All‐solid‐state lithium batteries are considered to be next‐generation devices for electrochemical energy storages due to their superiority in high safety and energy density. Sulfide electrolytes have become one of the most promising ion conductors due to their high ionic conductivities. At the same time, the favorable interface compatibility of sulfide electrolytes with sulfide‐based cathodes delivers bright prospect of all‐solid‐state lithium batteries.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Solid electrolytes have been considered as a promising approach for Li dendrite prevention because of their high mechanical strength and high Li transference number. However, recent reports indicate ...that Li dendrites also form in Li2S‐P2S5 based sulfide electrolytes at current densities much lower than that in the conventional liquid electrolytes. The methods of suppressing dendrite formation in sulfide electrolytes have rarely been reported because the mechanism for the “unexpected” dendrite formation is unclear, limiting the successful utilization of high‐energy Li anode with these electrolytes. Herein, the authors demonstrate that the Li dendrite formation in Li2S‐P2S5 glass can be effectively suppressed by tuning the composition of the solid electrolyte interphase (SEI) at the Li/electrolyte interface through incorporating LiI into the electrolyte. This approach introduces high ionic conductivity but electronic insulation of LiI in the SEI, and more importantly, improves the mobility of Li atoms, promoting the Li depositon at the interface and thus suppresses dendrite growth. It is shown that the critical current density is improved significantly after incorporating LiI into Li2S‐P2S5 glass, reaching 3.90 mA cm−2 at 100 °C after adding 30 mol% LiI. Stable cycling of the Li‐Li cells for 200 h is also achieved at 1.50 mA cm−2 at 100 °C.
The dendrite suppression capability of Li2S‐P2S5 glass electrolyte can be improved significantly by LiI incorporation, and the 70(0.75Li2S‐0.25P2S5)‐30LiI (LPS30I) electrolyte exhibits the highest capability for dendrite suppression. The critical current density of LPS30I reaches 3.90 mA cm−2 at 100 °C, and the Li/LPS30I/Li cell could cycle 200 h at 1.50 mA cm−2 at 100 °C.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Microplastic particles are a global concern due to their widespread and growing threat to marine and coastal environments. To improve knowledge of microplastic pollution in China, we investigated 25 ...sediment samples collected with a box corer in the Southern Yellow Sea and East China Sea off the coast of China. The microplastics were extracted from sediments via density separation, after which they were observed under a microscope and characterized according to shape, color, and size, while polymer type identification was performed using micro-Fourier transform infrared spectroscopy. The abundance of microplastics in the offshore region of the Southern Yellow Sea and East China Sea was mapped. The mean concentration of microplastics at the 25 sites was 13.4 ± 0.6 particles 100 g−1 dry weight (range: 6.0–24.0 particles 100 g−1 dry weight). Based on the categorization according to shape, color, and size, fiber (77%) was the most abundant shape, while blue (35%) and transparent (29%) were the most prevalent colors. In addition, the dominant size of microplastics was smaller than 1000 μm which accounted for 89%. Finally, polyethylene, polyethylene terephthalate, acrylic, polyester, cellulose, and cellophane were the most abundant types of microplastics identified. Our result highlighted the presence of microplastics in offshore sediments from the Yellow Sea and East China Sea, and provided useful information for evaluating the environmental risks posed by microplastics in China.
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•Microplastic pollution in offshore sediments from China was reported.•Abundance was correlated with site distance and grain size distribution.•Microplastics <1000 μm were the predominant size, accounting for 89%.•Cellophane and PET were the most common types of microplastic polymers.•This study offers useful data on microplastic pollution in offshore areas of China.
We clarified the state of microplastic particles, as ubiquitous and potentially toxic pollutants, in sediments off the coast of China.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Noticeable pseudo‐capacitance behavior out of charge storage mechanism (CSM) has attracted intensive studies because it can provide both high energy density and large output power. Although cyclic ...voltammetry is recognized as the feasible electrochemical technique to determine it quantitatively in the previous works, the results are inferior due to uncertainty in the definitions and application conditions. Herein, three successive treatments, including de‐polarization, de‐residual and de‐background, as well as a non‐linear fitting algorithm are employed for the first time to calibrate the different CSM contribution of three typical cathode materials, LiFePO4, LiMn2O4 and Na4Fe3(PO4)2P2O7, and achieve well‐separated physical capacitance, pseudo‐capacitance and diffusive contributions to the total capacity. This work can eliminate misunderstanding concepts and correct ambiguous results of the pseudo‐capacitance contribution and recognize the essence of CSM in electrode materials.
Well‐separated physical capacitance, pseudo‐capacitance, and diffusive capacity are achieved from the CV curves of typical electrode materials for metal‐ion batteries after three successive treatments including de‐polarization, de‐residual and de‐background as well as non‐linear fitting calculation, offering a more rational and reliable method to calculate the pseudo‐capacitance contribution.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The electrochemical stability window of solid electrolyte is overestimated by the conventional experimental method using a Li/electrolyte/inert metal semiblocking electrode because of the limited ...contact area between solid electrolyte and inert metal. Since the battery is cycled in the overestimated stability window, the decomposition of the solid electrolyte at the interfaces occurs but has been ignored as a cause for high interfacial resistances in previous studies, limiting the performance improvement of the bulk‐type solid‐state battery despite the decades of research efforts. Thus, there is an urgent need to identify the intrinsic stability window of the solid electrolyte. The thermodynamic electrochemical stability window of solid electrolytes is calculated using first principles computation methods, and an experimental method is developed to measure the intrinsic electrochemical stability window of solid electrolytes using a Li/electrolyte/electrolyte‐carbon cell. The most promising solid electrolytes, Li10GeP2S12 and cubic Li‐garnet Li7La3Zr2O12, are chosen as the model materials for sulfide and oxide solid electrolytes, respectively. The results provide valuable insights to address the most challenging problems of the interfacial stability and resistance in high‐performance solid‐state batteries.
The thermodynamic electrochemical stability windows of Li10GeP2S12 and Li7La3Zr2O12 are calculated using first principles computation method, and also experimentally validated using a Li/electrolyte/electrolyte‐carbon cell developed by us. Both solid electrolyte materials have narrower electrochemical windows than previously claimed by the battery community. These results can provide valuable information to address the most challenging interfacial problem for high‐performance all‐solid‐state batteries.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The commercialization of lithium–sulfur batteries is hindered by low cycle stability and low efficiency, which are induced by sulfur active material loss and polysulfide shuttle reaction through ...dissolution into electrolyte. In this study, sulfur-impregnated disordered carbon nanotubes are synthesized as cathode material for the lithium–sulfur battery. The obtained sulfur–carbon tube cathodes demonstrate superior cyclability and Coulombic efficiency. More importantly, the electrochemical characterization indicates a new stabilization mechanism of sulfur in carbon induced by heat treatment.
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IJS, KILJ, NUK, PNG, UL, UM
Microplastics are ubiquitous in marine environments. Sediments and marine organisms are recognized as the carriers and final destinations of microplastics. However, research on the concentration and ...abundance of microplastics in deep-sea sediments and organisms is limited. In this study, samples of sediments and organisms were collected from deep-sea locations of the western Pacific Ocean, with the depth ranging from 4601 m to 5732 m. Microplastics were extracted from the samples and analyzed by micro-Fourier-transform infrared spectroscopy. The average abundance of microplastics in the sediments was 240 items per kg dry weight of sediment. The microplastics were predominantly fibrous in shape (52.5%), blue in color (45.0%), and less than 1 mm in size (90.0%). The most commonly detected polymers were poly(propylene-ethylene) copolymer (40.0%) and polyethylene terephthalate (27.5%). The concentrations of polychlorinated biphenyls (PCBs), which are representatives of persistent organic pollutants, in the pore water of sediment samples were also investigated. A significant correlation between the distribution of microplastics and the PCB concentrations in sediments was found (P = 0.016). Microplastics were also detected in deep-sea organisms (i.e., Crinoidea, Pheronematidae, Ophiuroidea, and Gammaridea) in the sampling region, with an abundance of 0–3 items per individual biological sample. This assessment of microplastics in deep-sea sediments and benthic organisms of the western Pacific Ocean confirms that microplastic pollution exists in the deep-sea ecosystems of this region.
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•Microplastics in western Pacific deep-sea sediments and organisms were quantified.•Microplastics found were classified by shape, color, and size.•PP-PE and PET were the predominant types of polymers.•PCB concentration in sediment pore water was correlated to microplastic abundance.
The microplastic pollution in deep-sea sediments and organisms of the western Pacific Ocean were investigated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Aqueous Zn batteries are promising energy storage devices for large-scale energy-storage due to low cost and high energy density. However, their lifespan is limited by the water decomposition and Zn ...dendrite growth. Here, we suppress water reduction and Zn dendrite growth in dilute aqueous electrolyte by adding dimethyl sulfoxide (DMSO) into ZnCl2–H2O, in which DMSO replaces the H2O in Zn2+ solvation sheath due to a higher Gutmann donor number (29.8) of DMSO than that (18) of H2O. The preferential solvation of DMSO with Zn2+ and strong H2O–DMSO interaction inhibit the decomposition of solvated H2O. In addition, the decomposition of solvated DMSO forms Zn12(SO4)3Cl3(OH)15·5H2O, ZnSO3, and ZnS enriched-solid electrolyte interphase (SEI) preventing Zn dendrite and further suppressing water decomposition. The ZnCl2–H2O–DMSO electrolyte enables Zn anodes in Zn||Ti half-cell to achieve a high average Coulombic efficiency of 99.5% for 400 cycles (400 h), and the Zn||MnO2 full cell with a low capacity ratio of Zn:MnO2 at 2:1 to deliver a high energy density of 212 Wh/kg (based on both cathode and anode) and maitain 95.3% of the capacity over 500 cycles at 8 C.
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IJS, KILJ, NUK, PNG, UL, UM
Potassium ion batteries (PIBs) are recognized as one promising candidate for future energy storage devices due to their merits of cost‐effectiveness, high‐voltage, and high‐power operation. Many ...efforts have been devoted to the development of electrode materials and the progress has been well summarized in recent review papers. However, in addition to electrode materials, electrolytes also play a key role in determining the cell performance. Here, the research progress of electrolytes in PIBs is summarized, including organic liquid electrolytes, ionic liquid electrolytes, solid‐state electrolytes and aqueous electrolytes, and the engineering of the electrode/electrolyte interfaces is also thoroughly discussed. This Progress Report provides a comprehensive guidance on the design of electrolyte systems for development of high performance PIBs.
Electrolytes play a critical role in the electrochemical performance of emerging potassium‐ion batteries (PIBs). The research progress on electrolytes of PIBs is summarized in terms of fundamental properties, optimization of electrolyte components and engineering of electrode/electrolyte interfaces, providing a comprehensive guidance on designing more suitable electrolytes for high‐performance PIBs.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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