Abstract:is a promising cathode candidate for Li-ion batteries because of its high discharge capacity; however, its reaction mechanism during cycling has not been sufficiently explicated. Observations of Mn and O binding energy shifts in operando hard X-ray photoelectron spectroscopy measurements enabled us to determine the charge-compensation mechanism of Li 2 MnO 3 . The O 1s peak splits at an early stage during the first charge, and the concentration of lower-valence O changes reversibly with cycling, indicating the… Show more
“…Some studies have demonstrated very challenging operando XPS measurements. 197–199 Of course, ASSBs have the advantage to resist ultra-high vacuum, even though it was discussed previously that sulphide-based solid electrolytes might need to be cooled down to avoid sulphur sublimation. Still, the fabrication of cells that can be cycled inside the analysis chamber of the XPS instrument remains a challenge as it can be difficult already not under operando conditions.…”
Section: In Situ and Operando Xps Measurementsmentioning
Many of the challenges faced in the development of lithium-ion batteries (LIBs) and next-generation technologies stem from the (electro)chemical interactions between the electrolyte and electrodes during operation. It is at...
“…Some studies have demonstrated very challenging operando XPS measurements. 197–199 Of course, ASSBs have the advantage to resist ultra-high vacuum, even though it was discussed previously that sulphide-based solid electrolytes might need to be cooled down to avoid sulphur sublimation. Still, the fabrication of cells that can be cycled inside the analysis chamber of the XPS instrument remains a challenge as it can be difficult already not under operando conditions.…”
Section: In Situ and Operando Xps Measurementsmentioning
Many of the challenges faced in the development of lithium-ion batteries (LIBs) and next-generation technologies stem from the (electro)chemical interactions between the electrolyte and electrodes during operation. It is at...
“…The model all-solid-state battery designed in this study comprised a 10-nm Al current collector, 35.2-nm Li 2 MnO 3 cathode, 180-μm Li 1+ x + y Al x (Ti,Ge) 2− x Si y P 3− y O 12 (LASGTP) solid electrolyte, 500-nm Li 3 PO 4 buffer layer, and 1-μm Li anode 21 . The positions of the bands of the five components with respect to the vacuum level are shown in Fig.…”
Section: Resultsmentioning
confidence: 99%
“…This information has never been considered in battery development and serves as the starting point of this study. HAXPES and other methods were employed to elucidate the electrode reactions and properties, e.g., the crystal structure, formation and conversion of various redox species, and changes in the valences of the constituent elements during the charge–discharge reaction; these results, obtained via conventional investigations, have been described elsewhere 21 , 29 . Fig.…”
Section: Resultsmentioning
confidence: 99%
“…A model all-solid-state thin-film battery was studied to detect electronic structure changes and avoid the various complexities of a practical battery (consisting of powdered materials with coatings and additives; see Fig. 1 ) 21 . An unrivaled layered oxide, Li 2 MnO 3 , with a theoretical capacity of 459 mAh g –1 and maximum practical capacity of 300 mAh g –1 22 – 28 , was selected as the cathode.…”
Material characterization that informs research and development of batteries is generally based on well-established ex situ and in situ experimental methods that do not consider the band structure. This is because experimental extraction of structural information for liquid-electrolyte batteries is extremely challenging. However, this hole in the available experimental data negatively affects the development of new battery systems. Herein, we determined the entire band structure of a model thin-film solid-state battery with respect to an absolute potential using operando hard X-ray photoelectron spectroscopy by treating the battery as a semiconductor device. We confirmed drastic changes in the band structure during charging, such as interfacial band bending, and determined the electrolyte potential window and overpotential location at high voltage. This enabled us to identify possible interfacial side reactions, for example, the formation of the decomposition layer and the space charge layer. Notably, this information can only be obtained by evaluating the battery band structure during operation. The obtained insights deepen our understanding of battery reactions and provide a novel protocol for battery design.
“…All-inorganic solid-state batteries (AISSBs) attract great research interest due to the benefits in safety and energy density. , The thin-film battery, based on vacuum technology, is a type of AISSB that could reduce the thickness of solid-state electrolyte to a few microns and provide void-free electrode–electrolyte contact. − A mini-version of thin-film battery, referred to as a microbattery, is already utilized in chips, sensors, and other tiny devices. − The key step of fabricating a thin-film battery is the deposition technique.…”
All-inorganic solid-state batteries (AISSBs) attract great research interest due to the benefits in safety and energy density. The thinfilm battery, based on vacuum technology, is a type of AISSB that could reduce the thickness of a solid-state electrolyte to a few microns and provide void-free electrode−electrolyte contact. The key step of fabricating the thin-film battery is the deposition technique. Conventional pulsed laser deposition (PLD), which uses an excimer laser as energy source, is considered a promising technique but suffers from drawbacks like high cost, low speed, small scale, and consumption of rare/toxic working gases. Here, we introduce a high-repetition 1064 nm Nd:YAG fiber laser to replace the excimer laser for PLD application. This type of laser is solidstate and small in size, and its kHz to MHz repetition rate enables high deposition speed. This work focuses on the deposition of the LiCoO 2 electrode, as a demonstration of this novel PLD. The growth rate reached 1 nm/s in an area of ∼15 cm 2 . Controlling parameters such as vacuum level and substrate temperature (limited to 550 °C in this work) were explored. It was found that high-quality LiCoO 2 thin film prefers rough vacuum and high temperature. The electrochemical performances of the electrodes were evaluated in half-cells. The specific capacity is dependent on film thickness and charge/discharge rate: a value of 90 mAh/g was achieved for a 1.31 μm sample at 0.2 C, while 118 mAh/g was reached for a 0.27 μm sample at 0.5 C. The long-term cycling performance of a 0.43 μm sample showed 80% capacity retention after 565 charge−discharge cycles at 0.5 C. These preliminary results demonstrate that the Nd:YAG fiber-laser-based PLD can be a promising method for producing thin-film electrodes in large scale.
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