Enabling Uniform and Accurate Control of Cycling Pressure for All‐Solid‐State Batteries

Micrometer-sized layered oxide single crystals are considered promising cathode materials for all-solid-state batteries (ASSBs) due to their superior properties compared to those of polycrystalline forms. In addition, Liand Mn-rich layered oxides (LMRO), represented by the formula xLi 2 MnO 3 •(1− x)LiTMO 2 (where TM = Ni, Co, and Mn), are noted for their higher energy densities and cost-effectiveness relative to conventional layered Li-Ni 1−y−z Co y Mn z O 2 materials. In this regard, micrometer-sized, monodisperse, and discrete LMRO single crystals are synthesized using an active−inactive molten salt method that exploits the high reactivity of LiOH and the negligible reactivity of Li 2 SO 4 . This approach overcomes the challenges associated with conventional molten salt synthesis in controlling the structure and composition of LMRO. The chemical reactivities of lithium salts (LiOH, LiNO 3 , and Li 2 SO 4 ) with transition metal hydroxide precursors are examined to synthesize LMRO single crystals. Our findings show that LiOH and LiNO 3 are highly reactive, whereas Li 2 SO 4 remains significantly inert. For this reason, the active−active LiOH−LiNO 3 system forms the LMRO structure (0.73Li 2 MnO 3 •0.27Li[Ni 0.37 Co 0.63 ]O 2 ) with Mn-free NCM domains, regardless of the molar fractions of LiOH in LiOH−LiNO 3 . In contrast, the active−inactive LiOH−Li 2 SO 4 system undergoes significant transformations from spinel to layered structures upon variation of the molar fraction of LiOH. At a LiOH molar fraction of 0.82, this system ultimately forms monodisperse LMRO single crystals (0.65Li 2 MnO 3 •0.35Li[Ni 0.3 Co 0.5 Mn 0.2 ]O 2 ) with Mn-containing NCM domains. Moreover, LMRO single crystals are investigated as high-capacity cathode materials for ASSBs. In particular, LMRO single crystals (0.65Li 2 MnO 3 •0.35Li[Ni 0.3 Co 0.5 Mn 0.2 ]O 2 ) demonstrate excellent electrochemical performance in ASSBs, achieving high reversible capacities of 220 mA h g −1 and stable capacity retention over 300 cycles. These findings underscore the critical role of lithium salt reactivity in determining the structural and compositional characteristics of LMRO single crystals during synthesis, providing valuable insights for improving the electrochemical performance of high-capacity LMRO cathode materials in ASSBs.

show abstract

Automated Diagnosis of Performance Bottolenecks in Lithium-Sulfur Batteries

Parab,

Lee,

Miyagishima

et al. 2024

Preprint

View full text Add to dashboard Cite

Lithium-sulfur (Li-S) batteries offer high energy density and low cost, making them ideal for electric vehicles and aviation. However, the many factors affecting Li-S battery cycling performance complicate researchers' efforts to pinpoint the bottleneck. To address this, a toolkit called High-performance liquid chromatography, Ultraviolet spectroscopy, and Gas chromatography Sequential characterizations (HUGS) was developed using sequential analytical chemistry. Along with this, data analysis software Dr. HUGS© was created to automate the ‘diagnoses’ of the key degradation mechanisms, similar to a doctor assessing a patient. Our analysis reveals that carbon sulfur cathodes suffer capacity loss due to lithium sulfide buildup on the anode. HUGS shows that constant pressure setups in Li-S pouch cells improve compositional uniformity over constant gap setups. Conversely, sulfurized polyacrylonitrile batteries experience non-sulfide solid-electrolyte-interface formation and lithium pulverization—issues mitigated by localized high-concentration electrolytes. This work demonstrates how analytical chemistry techniques and automated data analysis can accelerate the diagnosis of the complexities of electrochemical systems, advancing next-generation, high-performance Li-S batteries.

show abstract

Enabling Uniform and Accurate Control of Cycling Pressure for All‐Solid‐State Batteries

Cited by 3 publications

References 62 publications

Sulfide-based solid electrolyte and electrode membranes for all-solid-state lithium batteries

Sulfide-based solid electrolyte and electrode membranes for all-solid-state lithium batteries

Active–Inactive Molten Salt Synthesis of Li- and Mn-Rich Layered Oxide Single Crystals as Cathode Materials for All-Solid-State Batteries

Automated Diagnosis of Performance Bottolenecks in Lithium-Sulfur Batteries

Contact Info

Product

Resources

About