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The effective flow of electrons through bulk electrodes is crucial for achieving high-performance batteries, although the poor conductivity of homocyclic sulfur molecules results in high barriers against the passage of electrons through electrode structures. This phenomenon causes incomplete reactions and the formation of metastable products. To enhance the performance of the electrode, it is important to place substitutable electrification units to accelerate the cleavage of sulfur molecules and increase the selectivity of stable products during charging and discharging. Herein, we develop a single-atom-charging strategy to address the electron transport issues in bulk sulfur electrodes. The establishment of the synergistic interaction between the adsorption model and electronic transfer helps us achieve a high level of selectivity towards the desirable short-chain sodium polysulfides during the practical battery test. These finding indicates that the atomic manganese sites have an enhanced ability to capture and donate electrons. Additionally, the charge transfer process facilitates the rearrangement of sodium ions, thereby accelerating the kinetics of the sodium ions through the electrostatic force. These combined effects improve pathway selectivity and conversion to stable products during the redox process, leading to superior electrochemical performance for room temperature sodium-sulfur batteries.

Tiivistelmä. Kansainvälinen verotus ja kansainväliseen verotukseen liittyvät kysymykset ovat herättäneet laajaa keskustelua erityisesti OECD:n käynnistämän veropohjan rapautumista ja voitonsiirtoa koskevan BEPS-hankkeen (Base Erosion and Profit Shifting) myötä. Kansainväliset yritykset hyödyntävät useita eri voitonsiirron kanavia kuten siirtohinnoittelua, lähipiirivelkaa ja hybridijärjestelyjen yhteensopimattomuustilanteita vähentääkseen yhteisöverotaakkaansa. Tutkielman tavoitteena oli selvittää voitonsiirron ja siirtohinnoittelun välistä yhteyttä kansainvälisesti toimivan yrityksen näkökulmasta. Tarkastelun keskiössä oli lisäksi OECD:n BEPS-hankkeen vaikutukset siirtohinnoitteluun. Tutkielmassa tarkasteltiin kansainvälisen voitonsiirron suuruusluokkaa,kannustimia, taloudellisia vaikutuksia sekä BEPS-hankkeen keinoja voitonsiirron ja veropohjan rapautumisen torjumiseen. Lisäksi tutkielmassa tutkittiin siirtohinnoittelun nykytilaa, siirtohinnoittelua BEPS-hankkeen tuomien uudistusten myötä sekä kansainvälisen verotuksen ongelmakohtia. Siirtohinnoittelulla on merkittävä vaikutus konserniyhtiöiden verotettavan tulon määrään sekä siihen, missä valtiossa tuloa verotetaan. Siirtohinnoittelu on keskeisessä osassa kansainvälisten konsernien liiketoimintaa mutta myös merkittävin kansainvälisten yritysten hyödyntämä voitonsiirron kanava. Siirtohinnoittelun tulee tulevaisuudessa vastata entistä paremmin taloudellista toimintaa ja arvonluontia. Erityisenä haasteena siirtohinnoittelulle nähdään aineettoman omaisuuden siirtohinnoittelu. BEPS-hankkeen uudistusten yhdistäminen olevassa oleviin siirtohinnoittelusäännöksiin tulee aiheuttamaan haasteita ja kustannuksia niin veroviranomaisille kuin kansainvälisille konserneille. Kansainvälisen verotusjärjestelmän uudistaminen on välttämätöntä, jotta tulevaisuuden verohaasteisiin, kuten digitalisaatioon, voidaan vastata. Yhtenäisemmän ja oikeudenmukaisemman kansainvälisen verotusjärjestelmän luominen luo pohjan reilulle kilpailulle ja

Rechargeable room-temperature sodium–sulfur (Na–S) and sodium–selenium (Na–Se) batteries are gaining extensive attention for potential large-scale energy storage applications owing to their low cost and high theoretical energy density. Optimization of electrode materials and investigation of mechanisms are essential to achieve high energy density and long-term cycling stability of Na–S(Se) batteries. Herein, we provide a comprehensive review of the recent progress in Na–S(Se) batteries. We elucidate the Na storage mechanisms and improvement strategies for battery performance. In particular, we discuss the advances in the development of battery components, including high-performance sulfur cathodes, optimized electrolytes, advanced Na metal anodes and modified separators. Combined with current research achievements, this review outlines remaining challenges and clear research directions for the future development of practical high-performance Na–S(Se) batteries. Graphic Abstract: [Figure not available: see fulltext.].

P’2-Na0.67Mn0.67Ni0.33O2 (NMNO) is one of the most promising cathodic materials for new generation sodium-ion batteries (SIBs). One drawback that is preventing its commercialization is however the high instability in the potential window 2.5–4.5 V vs. Na+/Na, caused by degradation reactions affecting the material's structure and composition. Herein we propose a strategy to overcome this weak spot introducing the surface coating of the material particles with inert magnesium oxide, that has been chosen as coating agent because of its low molecular weight. This protective layer is able to reduce the structural instability of the material without modifying the mixed conduction properties and thus globally stabilizing the electrochemical performances. In fact, the electrode of NMNO coated with 7 % of MgO, after an initial stabilization, was able to deliver over 90 mAh g−1 of reversible specific capacity at a current value of 50 mA g−1, with a capacity retention of 70 % after 250 cycles, to be compared with the 30 mAh g−1 of the uncoated material. The effect of the coating on the particles surface is here investigated with differential electrochemical mass spectrometry, to analyze the influence of the treatment on the electrode/electrolyte interphase.

Room temperature sodium sulfur (RT Na-S) batteries with high theoretical energy density and low cost have recently gained extensive attention for potential large-scale energy storage applications. However, the shuttle effect of sodium polysulfides is still the main challenge that leads to poor cycling stability, which hinders the practical application of RT Na-S batteries. Herein, a multifunctional hybrid MXene interlayer is designed to stabilize the cycling performance of RT Na-S batteries. The hybrid MXene interlayer comprises a large-sized Ti3C2Tx nanosheets inner layer followed by a small-sized Mo2Ti2C3Tx nanoflake outer layer on the surface of the glass fiber (GF) separator. The large-sized Ti3C2Tx nanosheet inner layer provides an effective physical block and chemical confinement for the soluble polysulfides. The small-sized Mo2Ti2C3Tx outer layer offers an excellent polysulfide trapping capability and accelerates the reaction kinetics of polysulfide conversion, due to its superior electronic conductivity, large specific surface area, and Mo-rich catalytic surfaces. As a result, RT Na-S batteries with this hybrid MXene interlayer modified glass fiber separator deliver a stable cycling performance over 200 cycles at 1 C with an enhanced capacity retention of 71%. This unique structure design provides a novel strategy to develop 2D material-based functional interlayer for high-performance metal-sulfur batteries.

Incorporation of various transition metals has been shown to improve the electrochemical performance of Mn-rich Na-ion cathode materials. A greater comprehension of the role of dopant ions, particularly with regard to Mn-rich layered oxides as materials for the positive electrode of Na-ion batteries, is required for their continual development. Here two similar series of Mn-rich P2 cathode materials P2-Na2/3Mn0.8M0.1M′0.1O2 (M = Fe, Zn and M′ = Cu, Al, Ti) are explored, focusing on structural analysis using high-resolution operando synchrotron X-ray diffraction. Notably, under the cycling conditions employed, no P2 to O2 phase transitions toward the charged state were identified for any of the materials investigated. Particularly stable solid solution evolution was observed for P2-Na2/3Mn0.8Zn0.1Cu0.1O2 and P2-Na2/3Mn0.8Zn0.1Al0.1O2 when cycled at 40 mA.g-1 which reflects the electrochemical properties of the materials investigated herein and illustrates that Zn is an excellent choice of dopant for Mn-rich cathode materials. Moreover, the better cyclability of P2-Na2/3Mn0.8Zn0.1Al0.1O2 compared with P2-Na2/3Mn0.8Zn0.1Cu0.1O2 is in keeping with the minimal structural changes observed. This demonstrates that although oxidation state predictions to optimize the initial Mn oxidation state are a good way of initially selecting materials, to truly exploit Mn-rich P2-type materials it is necessary to build up an in-depth understanding of both oxidation states and the associated Jahn-Teller distortion as well as the subtle interplay of synergistic and antagonistic interactions between dopants. Overall, this study illustrates the value of structural investigations to assist in the rational design and validation of novel high-performance materials; the results highlight that the interplay between dopants in addition to the average Mn oxidation state are both crucial considerations when designing high-performance Mn-rich layered oxide materials.

The current Li-based battery technology is limited in terms of energy contents. Therefore, several approaches are considered to improve the energy density of these energy storage devices. Here, we report the combination of a heteroatom-based gel polymer electrolyte with a hybrid cathode comprising of a Li-rich oxide active material and graphite conductive agent to produce a high-energy "shuttle-relay" Li metal battery, where additional capacity is generated from the electrolyte's anion shuttling at high voltages. The gel polymer electrolyte, prepared via in situ polymerization in an all-fluorinated electrolyte, shows adequate ionic conductivity (around 2 mS cm-1 at 25 °C), oxidation stability (up to 5.5 V vs Li/Li+), compatibility with Li metal and safety aspects (i.e., non-flammability). The polymeric electrolyte allows for a reversible insertion of hexafluorophosphate anions into the conductive graphite (i.e., dual-ion mechanism) after the removal of Li ions from Li-rich oxide (i.e., rocking-chair mechanism).