Effect of Nanoparticles in LiFePO4 Cathode Material Using Organic/Inorganic Composite Solid Electrolyte for All-Solid-State Batteries.

Herein, we report the effect of using nanoparticles of LiFePO4 on the electrochemical properties of all-solid-state batteries (ASSBs) with a solid electrolyte. LiFePO4 (LFP) cathode materials are promising cathode materials in polymer-based composite solid electrolytes because of their limited electrochemical window range. However, LFP cathodes exhibit poor electric conductivity and sluggish lithium ion diffusion. In addition, there is a disadvantage in that the interfacial resistance increases due to poor contact between the LFP cathode material and the solid electrolyte when composing the composite cathode. The nano-sized LFP cathode material increases the contact area between solid electrolyte in the positive electrode and enhances lithium ion diffusion. Therefore, the structural differences and electrochemical performance of these nanoscale LFP cathode materials in the ASSB were studied by X-ray diffraction, scanning electron microscopy, and electrochemical analysis.

Effect of a self-assembling La2(Ni0.5Li0.5)O4 and amorphous garnet-type solid electrolyte composite on a layered cathode material in all-solid-state batteries.

In this article, we report the effect of a Li6.75La3Zr2Al0.25O12 (LLZAO) composite Li(Ni0.8Co0.1Mn0.1)O2 (NCM811) cathode material on the performance of all-solid-state batteries (ASSBs) with oxide-based organic/inorganic hybrid solid electrolytes. The layered structure of Ni-rich cathode material Li(Ni x Co(1-x)/2Mn(1-x)/2)O2 (x > 0.6) (NCM) exhibiting a high specific capacity is among the suitable cathode materials for next-generation energy storage systems, particularly electric vehicles and portable devices for all-solid-state batteries. However, the ASSBs present a problem-the resistance at the interface between a cathode and solid electrolyte is larger than that with a liquid electrolyte because of point contact. To solve this problem, using a simultaneous co-precipitation method, we composited various amounts of LLZAO material and an ion conducting material on the cathode material's surface. Therefore, to optimize the value of the LLZAO material in the composite cathode material, the structure, cycling stability, and rate performance of the NCM-LLZAO composite cathode material in ASSBs with oxide-based inorganic/organic-hybrid electrolytes were investigated using powder X-ray diffraction analysis, field-emission scanning electron microscopy, electrochemical impedance spectroscopy, and galvanostatic measurements.

Lithium-ion transport in inorganic active fillers used in PEO-based composite solid electrolyte sheets.

In this study, we evaluated the properties exhibited by a composite solid electrolyte (CSE) prepared via tailoring the particle size of an active filler, Li6.4La3Zr1.4Ta0.6O12 (LLZTO). The average particle size was reduced to 2.53 µm via ball milling and exhibited a specific surface area of 3.013 m2 g-1. Various CSEs were prepared by combining PEO and LLZTO/BM-LLZTO. The calculated lithium ionic conductivity of the BM-LLZTO CSE was 6.0 × 10-5 S cm-1, which was higher than that exhibited by the LLZTO CSE (4.6 × 10-5 S cm-1). This result was confirmed via 7Li nuclear magnetic resonance (NMR) analysis, during which lithium-ion transport pathways varied as a function of the particle size. NMR analysis showed that when BM-LLZTO was used, the migration of Li ions through the interface occurred at a fast rate owing to the small size of the constituent particles. During the Li/CSEs/Li symmetric cell experiment, the BM-LLZTO CSE exhibited lower overvoltage characteristics than the LLZTO CSE. A comparison of the characteristics exhibited by the LFP/CSEs/Li cells confirmed that the cells using BM-LLZTO exhibited high discharge capacity, rate performance, and cycling stability irrespective of the CSE thickness.