Kazuaki Kisu

Magnesium borohydride ammonia borane, Mg(BH4)2(NH3BH3)2, was electrochemically investigated. Impedance measurements of the mechanochemically synthesized Mg(BH4)2(NH3BH3)2 exhibited an ionic conductivity of 1.3 × 10–5 S cm–1 at 30 °C. Electrochemical cells fabricated with Mg(BH4)2(NH3BH3)2 as the solid electrolyte demonstrated reversible Mg migration through the material, indicating its potential for use as a Mg ionic conductor in all-solid-state Mg-ion batteries.

High-energy-density and low-cost calcium (Ca) batteries have been proposed as 'beyond-Li-ion' electrochemical energy storage devices. However, they have seen limited progress due to challenges associated with developing electrolytes showing reductive/oxidative stabilities and high ionic conductivities. This paper describes a calcium monocarborane cluster salt in a mixed solvent as a Ca-battery electrolyte with high anodic stability (up to 4 V vs. Ca²⁺/Ca), high ionic conductivity (4 m

Single-nanocrystalline SnO₂ particles encapsulated within hollow-structured carbon structures were synthesized. Encapsulated SnO₂ is readily transformed into a blended amorphous structure composed of Li_xSnO_1.45 (<italic>x</italic> = 0–7.3) after repeated lithiation–delithiation processes.

Spherical LiMn_0.792Fe_0.198Mg_0.010PO₄nanocrystals, which are highly dispersed and encapsulated within the interstices of supergrowth (single-walled) carbon nanotubes (SGCNTs), were successfully synthesized by<italic>in situ</italic>material processing technology called “ultra-centrifuging (UC) treatment”.

As potential alternatives to Li-ion batteries, rechargeable Ca metal batteries offer advantageous features such as high energy density, cost-effectiveness, and natural elemental abundance. However, challenges, such as Ca metal passivation by electrolytes and a lack of cathode materials with efficient Ca²⁺ storage capabilities, impede the development of practical Ca metal batteries. To overcome these limitations, the applicability of a CuS cathode in Ca metal batteries and its electroc

Water molecules are exchanged in the crystal structure, which imparts a high divalent conductivity to hydrated complex hydrides. MB 12 H 12 ·12H 2 O (M = Zn or Mg) exhibits exceptional conductivities higher than those of less-hydrated complex hydrides.

Rechargeable Ca batteries offer the advantages of high energy density, low cost, and earth-abundant constituents, presenting a viable alternative to lithium-ion batteries. However, using polymer electrolytes in practical Ca batteries is not often reported, despite its potential to prevent leakage and preserve battery flexibility. Herein, a Ca(BH₄)₂-based gel-polymer electrolyte (GPE) is prepared from Ca(BH₄)₂ and poly(tetrahydrofuran) (pTHF) and tested

Multivalent-ion and all-solid-state batteries have emerged as potential solutions to address resource concerns and safety issues.

The use of Ca metal in battery technology is a promising approach owing to its high energy density and sustainability. However, the increased battery resistance during extended cycling significantly narrows its application range. This study aimed to improve the long-term stability of Ca deposition by employing a dual-salt strategy based on calcium monocarborane, Ca(CB₁₁H₁₂)₂, which demonstrated favorable Ca deposition characteristics as a single-salt electrolyte.

Efficient Ca plating/stripping and the development of low-volatility electrolytes remain key challenges for the broad-scale application of Ca metal batteries. In this study, we demonstrate that CaBr₂ addition modifies the electrolyte environment, enabling highly reversible Ca plating/stripping in electrolytes based on low-volatility diglyme as a solvent previously considered nonfunctional.

1. Introduction Olivine phosphates have long been investigated as cathode material in Li-ion batteries. In particular, lithium iron phosphate (LiFePO 4 ) has attracted the attention of many researchers because of its high theoretical capacity of 170 mAh g -1 , low cost and high electrochemical/thermal stabilities of the phosphate (PO 4 3- ) anion [1] . However, the large volume difference during two-phase reaction between Li-rich Li 1-a FePO 4 (LFP) and Li-poor Li b FePO 4 (FP) phases leads to l