The first anionic thia-fries rearrangement at arene tricarbonylchromium complexes and reactions of phthalimide tricarbonylchromium complexes

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Towards stable and efficient electrolytes for room-temperature rechargeable calcium batteries

Rechargeable calcium (Ca) batteries have the prospect of highenergy and low-cost. However, the development of Ca batteries is hindered due to the lack of efficient electrolytes. Herein, we report novel calcium tetrakis(hexafluoroisopropyloxy)borate Ca[B(hfip)₄]₂ based electrolytes exhibiting reversible Ca deposition at room temperature, a high oxidative stability up to 4.5 V and high ionic conductivity >8 mS cm¯¹. This finding opens a new approach towards room-temperature rechargeable calcium batteries

Cathode Materials and Chemistries for Magnesium Batteries: Challenges and Opportunities

Rechargeable magnesium batteries hold promise for providing high energy density, material sustainability, and safety features, attracting increasing research interest as post-lithium batteries. With the progressive development of Mg electrolytes with enhanced (electro-)chemical stability, tremendous efforts have been devoted to the exploration of high-energy cathode materials. In this review, recent findings related to Mg cathode chemistry are summarized, focusing on the strategies that promote Mg2+ diffusion by targeting its interaction with the cathode hosts. The critical role of the cathode–electrolyte interfaces is elaborated, which remains largely unexplored in Mg systems. The approaches to optimization of cathode–electrolyte combinations to unlock the kinetic limitations of Mg2+ diffusion, enabling fast electrochemical processes of the cathodes, are highlighted. Furthermore, representative conversion chemistries and coordination chemistries that bypass bulk Mg2+ diffusion are discussed, with particular attention given to their key challenges and prospects. Finally, the hybrid systems that combine the fast kinetics of the monovalent cathode chemistries and high-capacity Mg anodes are revisited, calling for further practical evaluation of this promising strategy. All in all, the aim is to provide fundamental insights into the cathode chemistry, which promotes the material development and interfacial regulations toward practical high-performance Mg batteries

Beyond Intercalation Chemistry for Rechargeable Mg Batteries: A Short Review and Perspective

Rechargeable magnesium (Mg) batteries are an attractive candidate for next-generation battery technology because of their potential to offer high energy density, low cost, and safe use. Despite recent substantial progress achieved in the development of efficient electrolytes, identifying high-performance cathode materials remains a bottleneck for the realization of practical Mg batteries. Due to the strong interaction between the doubly charged Mg2+ ions and the host matrix, most of the conventional intercalation cathodes suffer from low capacity, high voltage hysteresis, and low energy density in Mg based battery systems. Alternatively, the thermodynamically favorable conversion reaction may circumvent the sluggish Mg2+ diffusion kinetics. In this review, the focus will be laid on promising cathodes beyond the typical intercalation-type materials. We will give an overview of the recent emerging Mg systems with conversion-type and organic cathodes

Calcium-tin alloys as anodes for rechargeable non-aqueous calcium-ion batteries at room temperature

Rechargeable calcium batteries possess attractive features for sustainable energy-storage solutions owing to their high theoretical energy densities, safety aspects and abundant natural resources. However, divalent Ca-ions and reactive Ca metal strongly interact with cathode materials and non-aqueous electrolyte solutions, leading to high charge-transfer barriers at the electrode-electrolyte interface and consequently low electrochemical performance. Here, we demonstrate the feasibility and elucidate the electrochemical properties of calcium-tin (Ca–Sn) alloy anodes for Ca-ion chemistries. Crystallographic and microstructural characterizations reveal that Sn formed from electrochemically dealloying the Ca–Sn alloy possesses unique properties, and that this in-situ formed Sn undergoes subsequent reversible calciation/decalciation as CaSn(3). As demonstration of the suitability of Ca–Sn alloys as anodes for Ca-ion batteries, we assemble coin cells with an organic cathode (1,4-polyanthraquinone) in an electrolyte of 0.25 M calcium tetrakis(hexafluoroisopropyloxy)borate in dimethoxyethane. These electrochemical cells are charged/discharged for 5000 cycles at 260 mA g(−1), retaining a capacity of 78 mAh g(−1) with respect to the organic cathode. The discovery of new class of Ca–Sn alloy anodes opens a promising avenue towards viable high-performance Ca-ion batteries

Environmental assessment of a new generation battery: The magnesium-sulfur system

As environmental concerns mostly drive the electrification of our economy and the corresponding increase in demand for battery storage systems, information about the potential environmental impacts of the different battery systems is required. However, this kind of information is scarce for emerging post-lithium systems such as the magnesium-sulfur (MgS) battery. Therefore, we use life cycle assessment following a cradle-to-gate perspective to quantify the cumulative energy demand and potential environmental impacts per Wh of the storage capacity of a hypothetical MgS battery (46 Wh/kg). Furthermore, we also estimate global warming potential (0.33 kg CO2 eq/Wh) , fossil depletion potential (0.09 kg oil eq / Wh), ozone depletion potential (2.5E-08 kg CFC-11/Wh) and metal depletion potential (0.044 kg Fe eq/Wh), associated with the MgS battery production. The battery is modelled based on an existing prototype MgS pouch cell and hypothetically optimised according to the current state of the art in lithium-ion batteries (LIB), exploring future improvement potentials. It turns out that the initial (non-optimised) prototype cell cannot compete with current LIB in terms of energy density or environmental performance, mainly due to the high share of non-active components, decreasing its performance substantially. Therefore, if the assumed evolutions of the MgS cell composition are achieved to overcome current design hurdles and reach a comparable lifespan, efficiency, cost and safety levels to that of existing LIB; then the MgS battery has significant potential to outperform both existing LIB, and lithium-sulfur batteries

Fast kinetics of multivalent intercalation chemistry enabled by solvated magnesium-ions into self-established metallic layered materials

Rechargeable magnesium batteries are one of the most promising candidates for next-generation battery technologies. Despite recent significant progress in the development of efficient electrolytes, an on-going challenge for realization of rechargeable magnesium batteries remains to overcome the sluggish kinetics caused by the strong interaction between double charged magnesium-ions and the intercalation host. Herein, we report that a magnesium battery chemistry with fast intercalation kinetics in the layered molybdenum disulfide structures can be enabled by using solvated magnesium-ions ([Mg(DME)x]2+). Our study demonstrates that the high charge density of magnesium-ion may be mitigated through dimethoxyethane solvation, which avoids the sluggish desolvation process at the cathode-electrolyte interfaces and reduces the trapping force of the cathode lattice to the cations, facilitating magnesium-ion diffusion. The concept of using solvation effect could be a general and effective route to tackle the sluggish intercalation kinetics of magnesium-ions, which can potentially be extended to other host structures