A 3.2 V Binary Layered Oxide Cathode for Potassium-Ion Batteries.

Potassium-ion batteries (KIBs) can offer high energy density, cyclability, and operational safety while being economical due to the natural abundance of potassium. Utilizing graphite as an anode, suitable cathodes can realize full cells. Searching for potential cathodes, this work introduces P3-type KNiMnO layered oxide as a potential candidate synthesized by a simple solid-state method.

Optical Study of the Surface Film Formed during Li-Metal Deposition and Dissolution Investigated by Surface Plasmon Resonance Spectroscopy.

The features of the electrode surface film during Li-metal deposition and dissolution cycles are essential for understanding the mechanism of the negative electrode reaction in Li-metal battery cells. The physical and chemical property changes of the interface during the initial stages of the reaction should be investigated under operando conditions. In this study, we focused on the changes in the optical properties of the electrode surface film of the negative electrode of a Li-metal battery.

Mixed alkali-ion transport and storage in atomic-disordered honeycomb layered NaKNiTeO.

Honeycomb layered oxides constitute an emerging class of materials that show interesting physicochemical and electrochemical properties. However, the development of these materials is still limited. Here, we report the combined use of alkali atoms (Na and K) to produce a mixed-alkali honeycomb layered oxide material, namely, NaKNiTeO.

Electrochemical Surface Plasmon Resonance Spectroscopy for Investigation of the Initial Process of Lithium Metal Deposition.

The initial process of Li-metal electrodeposition on the negative electrode surface determines the charging performance of Li-metal secondary batteries. However, minute depositions or the early processes of nucleation and growth of Li metal are generally difficult to detect under operando conditions. In this study, we propose an optical diagnostic approach to address these challenges.

Ether-Functionalized Pyrrolidinium-Based Room Temperature Ionic Liquids: Physicochemical Properties, Molecular Dynamics, and the Lithium Ion Coordination Environment.

The physicochemical properties of room temperature ionic liquids (RTILs) consisting of bis(trifluoromethanesulfonyl)amide (TFSA ) combined with 1-hexyl-1-methylpyrrolidinium (Pyr ), 1-(butoxymethyl)-1-methylpyrrolidinium (Pyr ), 1-(4-methoxybutyl)-1-methyl pyrrolidinium (Pyr ), and 1-((2-methoxyethoxy)methyl)-1-methylpyrrolidinium (Pyr ) were investigated using both experimental and computational approaches. Pyr TFSA, which contains two ether oxygen atoms, showed the lowest viscosity, and the relationship between its physicochemical properties and the position and number of the ether oxygen atoms was discussed by a careful comparison with Pyr TFSA and Pyr TFSA. Ab initio calculations revealed the conformational flexibility of the side chain containing the ether oxygen atoms.

Correction: The effects of the position of the ether oxygen atom in pyrrolidinium-based room temperature ionic liquids on their physicochemical properties.

Correction for 'The effects of the position of the ether oxygen atom in pyrrolidinium-based room temperature ionic liquids on their physicochemical properties' by Kazuki Yoshii et al., Phys. Chem.

The effects of the position of the ether oxygen atom in pyrrolidinium-based room temperature ionic liquids on their physicochemical properties.

Room temperature ionic liquids (RTILs) containing ether oxygen atoms have been investigated for a gamut of science and technology applications owing to their superior physicochemical properties. However, the effect of the position of the ether oxygen atom in the side chain on their physicochemical properties is not clearly understood. This study investigates, using both experimental and computational approaches, the effect of ether oxygen atoms on the physicochemical properties of RTILs consisting of bis(trifluoromethylsulfonyl)amide (TFSA-) with 1-methyl-1-propylpyrrolidinium (MPP+), 1-butyl-1-methylpyrrolidinium (BMP+), 1-methoxymethyl-1-methylpyrrolidinium (MOMMP+), 1-ethoxymethyl-1-methylpyrrolidinium (EOMMP+), and 1-methoxyethyl-1-methylpyrrolidinium (MOEMP+).

New insight derived from a two-compartment cell: electrochemical behavior of FeF positive electrode.

A designed two-compartment cell was applied to the degradation analysis of FeF3 having high theoretical energy density. Comparing with the result of the coin cell, the two-compartment cell gave us insight that the elution of Fe was responsible for the degradation of FeF3 and LiDFOB was found as an essentially effective additive for suppressing the degradation of FeF3.

Development of a half-cell for x-ray structural analysis of liquid electrolytes in rechargeable batteries.

A half-cell of the rechargeable Li-ion battery was developed to characterize an electrolyte structure using high energy x-ray total scattering measurements in combination with a two-dimensional x-ray detector. The scattering pattern consisted of strong Bragg peaks from electrodes and diffuse scatterings from sapphire windows, in addition to a weak halo pattern from the electrolyte. By selectively removing the signals of the electrodes and windows using specific numerical procedures, we could successfully extract the structural information of the electrolyte, which was in reasonable agreement with the reference data obtained from the electrolyte in a glass capillary.

A high voltage honeycomb layered cathode framework for rechargeable potassium-ion battery: P2-type KNiCoTeO.

The designing of high voltage cathode materials is critical for the advancement of potassium-ion (K-ion) battery. Herein, we present a new honeycomb framework P2-type K2/3Ni1/3Co1/3Te1/3O2 (or equivalently written as K2NiCoTeO6) which exhibits the highest voltage on record (beyond 4 V versus K+/K) for layered cathode materials. This work will allow for the further development of, particularly, high voltage layered cathodes for K-ion battery.

Rechargeable potassium-ion batteries with honeycomb-layered tellurates as high voltage cathodes and fast potassium-ion conductors.

Rechargeable potassium-ion batteries have been gaining traction as not only promising low-cost alternatives to lithium-ion technology, but also as high-voltage energy storage systems. However, their development and sustainability are plagued by the lack of suitable electrode materials capable of allowing the reversible insertion of the large potassium ions. Here, exploration of the database for potassium-based materials has led us to discover potassium ion conducting layered honeycomb frameworks.

Alkali Metal Salts with Designable Aryltrifluoroborate Anions.

Aryltrifluoroborate ([ArBF3](-)) has a designable basic anion structure. Various [ArBF3](-)-based anions were synthesized to create novel alkali metal salts using a simple and safe process. Nearly 40 novel alkali metal salts were successfully obtained, and their physicochemical characteristics, particularly their thermal properties, were elucidated.

Polymer gel electrolytes for application in aluminum deposition and rechargeable aluminum ion batteries.

A polymer gel electrolyte using AlCl3 complexed acrylamide as a functional monomer and acidic ionic liquid based on a mixture of 1-ethyl-3-methylimidazolium chloride (EMImCl) and AlCl3 (EMImCl-AlCl3, 1-1.5, in molar ratio) as a plasticizer has been successfully prepared for the first time via free radical polymerization. Aluminum deposition is successfully achieved using a polymer gel electrolyte containing 80 wt% ionic liquid.

Physicochemical properties of tri-n-butylalkylphosphonium cation-based room-temperature ionic liquids.

The physicochemical properties of novel four tri-n-butylalkylphosphonium-based room-temperature ionic liquids (RTILs), tri-n-butylmethylphosphonium dimethylphosphate ([P(4,4,4,1)][DMP]), tri-n-butyl(2-hydroxymethyl)phosphonium bis(trifluoromethylsulfonyl)amide ([P(4,4,4,2OH)][Tf2N]), tetra-n-butylphosphonium O,O'-diethylphosphorodithioate ([P(4,4,4,4)][DEPDT]), and tri-n-butyldodecylphosphonium 3,5-bis(methoxycarbonyl)benzenesulfonate ([P(4,4,4,12)][MCBS]), were examined in this study. All RTILs showed a favorable thermal decomposition temperature exceeding 560 K. Of these, [P(4,4,4,12)][MCBS] exhibited a fairly high thermal stability compared with common phosphonium cation-based RTILs reported to date.