23 research outputs found
Quantitative Analysis of Sodium Metal Deposition and Interphase in Na Metal Batteries
Sodium-ion batteries exhibit significant promise as a viable alternative to
current lithium-ion technologies owing to their sustainability, low cost per
energy density, reliability, and safety. Despite recent advancements in cathode
materials for this category of energy storage systems, the primary challenge in
realizing practical applications of sodium-ion systems is the absence of an
anode system with high energy density and durability. Although Na metal is the
ultimate anode that can facilitate high-energy sodium-ion batteries, its use
remains limited due to safety concerns and the high-capacity loss associated
with the high reactivity of Na metal. In this study, titration gas
chromatography is employed to accurately quantify the sodium inventory loss in
ether- and carbonate-based electrolytes. Uniaxial pressure is developed as a
powerful tool to control the deposition of sodium metal with dense morphology,
thereby enabling high initial coulombic efficiencies. In ether-based
electrolytes, the Na metal surface exhibits the presence of a uniform solid
electrolyte interphase layer, primarily characterized by favorable inorganic
chemical components with close-packed structures. The full cell, utilizing a
controlled electroplated sodium metal in ether-based electrolyte, provides
capacity retention of 91.84% after 500 cycles at 2C current rate and delivers
86 mAh/g discharge capacity at 45C current rate, suggesting the potential to
enable Na metal in the next generation of sodium-ion technologies with
specifications close to practical requirements
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Design principles for enabling an anode-free sodium all-solid-state battery
Anode-free batteries possess the optimal cell architecture due to their reduced weight, volume and cost. However, their implementation has been limited by unstable anode morphological changes and anodeâliquid electrolyte interface reactions. Here we show that an electrochemically stable solid electrolyte and the application of stack pressure can solve these issues by enabling the deposition of dense sodium metal. Furthermore, an aluminium current collector is found to achieve intimate solidâsolid contact with the solid electrolyte, which allows highly reversible sodium plating and stripping at both high areal capacities and current densities, previously unobtainable with conventional aluminium foil. A sodium anode-free all-solid-state battery full cell is demonstrated with stable cycling for several hundred cycles. This cell architecture serves as a future direction for other battery chemistries to enable low-cost, high-energy-density and fast-charging batteries
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A Facile, Dry-Processed Lithium Borate-Based Cathode Coating for Improved All-Solid-State Battery Performance
Sulfide-based solid electrolytes are known to have narrow electrochemical windows which limit their practical use in all-solid-state batteries (ASSBs). Specifically, when paired with a high-voltage transition metal oxide (TMO) cathode, the electrolyte will typically undergo unwanted degradation via chemical reactions or electrochemical oxidation, especially upon charging to voltages beyond the electrochemical stability window of the electrolyte. To mitigate these undesired reactions, thin (<10 nm), conformal, ionically-conducting, and electronically-insulating oxide-based protective coating layers have been applied on the cathode, typically via a solution process. In this work, a lithium borate-based (LBO) coating, prepared instead with a dry coating process, was shown to have the same beneficial properties. As evidenced by electrochemical characterization, the developed LBO coating shows good cycling performance and even performs better than the LiNbO3 coating commonly used in the literature. This new solvent-free coating method can thus be used to fabricate longer-lasting ASSBs
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A Facile, Dry-Processed Lithium Borate-Based Cathode Coating for Improved All-Solid-State Battery Performance
Sulfide-based solid electrolytes are known to have narrow electrochemical windows which limit their practical use in all-solid-state batteries (ASSBs). Specifically, when paired with a high-voltage transition metal oxide (TMO) cathode, the electrolyte will typically undergo unwanted degradation via chemical reactions or electrochemical oxidation, especially upon charging to voltages beyond the electrochemical stability window of the electrolyte. To mitigate these undesired reactions, thin (<10 nm), conformal, ionically-conducting, and electronically-insulating oxide-based protective coating layers have been applied on the cathode, typically via a solution process. In this work, a lithium borate-based (LBO) coating, prepared instead with a dry coating process, was shown to have the same beneficial properties. As evidenced by electrochemical characterization, the developed LBO coating shows good cycling performance and even performs better than the LiNbO3 coating commonly used in the literature. This new solvent-free coating method can thus be used to fabricate longer-lasting ASSBs
Fabrication of High-Quality Thin Solid-State Electrolyte Films Assisted by Machine Learning
International audienceSolid-state electrolytes (SSEs) are promising candidates to circumvent flammability concerns of liquid electrolytes. However, enhancing energy densities by thinning SSE layers and enabling scalable coating processes remain challenging. While previous studies have addressed thin and flexible SSEs, mainly ionic conductivity was considered for performance evaluation, and no systematic research on the effects of manufacturing conditions on the quality of SSE films was performed. Here, both uniformity and ionic conductivity are considered for evaluating the SSE films under the guidance of machine learning (ML). Three algorithms, principal component analysis, K-means clustering, and support vector machine, are employed to decipher the interdependencies between manufacturing conditions and film performance. Guided by ML, a 40 mu m SSE film with high ionic conductivity and good uniformity is used to construct a LiNi0.8Co0.1Mn0.1O2 parallel to Li6PS5Cl parallel to LiIn cell demonstrating 100 cycles. This study presents an efficient ML-assisted approach to optimize scalable production of high-quality SSE films
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New insights into Li distribution in the superionic argyrodite Li6PS5Cl.
By using temperature-dependent neutron powder diffraction combined with maximum entropy method analysis, a previously unreported Li lattice site was discovered in the argyrodite Li6PS5Cl solid-state electrolyte. This new finding enables a more complete description of the Li diffusion model in argyrodites, providing structural guidance for designing novel high-conductivity solid-state electrolytes
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Quantitative analysis of sodium metal deposition and interphase in Na metal batteries
Sodium-ion batteries exhibit significant promise as a viable alternative to current lithium-ion technologies owing to their sustainability, low cost per energy density, reliability, and safety. Despite recent advancements in cathode materials for this category of energy storage systems, the primary challenge in realizing practical applications of sodium-ion systems is the absence of an anode system with high energy density and durability. Although Na metal is the ultimate anode that can facilitate high-energy sodium-ion batteries, its use remains limited due to safety concerns and the high-capacity loss associated with the high reactivity of Na metal. In this study, titration gas chromatography is employed to accurately quantify the sodium inventory loss in ether- and carbonate-based electrolytes. Uniaxial pressure is developed as a powerful tool to control the deposition of sodium metal with dense morphology, thereby enabling high initial coulombic efficiencies. In ether-based electrolytes, the Na metal surface exhibits the presence of a uniform solid electrolyte interphase layer, primarily characterized by favorable inorganic chemical components with close-packed structures. The full cell, utilizing a controlled electroplated sodium metal in ether-based electrolyte, provides capacity retention of 91.84% after 500 cycles at 2C current rate and delivers 86 mA h gâ1 discharge capacity at 45C current rate, suggesting the potential to enable Na metal in the next generation of sodium-ion technologies with specifications close to practical requirements
High-performing All-solid-state Sodium-ion Batteries Enabled by the Presodiation of Hard Carbon
All-solid-state sodium ion batteries (AS3iBs) are highly sought after for stationary energy storage systems due to their suitable safety and stability over a wide temperature range. Hard carbon (HC), which is low cost, exhibits a low redox potential, and a high capacity, is integral to achieve a practical large-scale sodium-ion battery. However, the energy density of the battery utilizing this anode material is hampered by its low initial Coulombic efficiency (ICE). Herein, two strategies, namely (i) thermal treatment and (ii) presodiation by thermal decomposition of NaBH4, are explored to improve the ICE of pristine HC. Raman spectroscopy, X-ray photoelectron spectroscopy and electrochemical characterizations elucidate that the thermal treatment increases the Csp2 content in the HC structure, while the presodiation supplies the sodium to occupy the intrinsic irreversible sites. Consequently, presodiated HC exhibits an outstanding ICE (>99%) compared to the thermally treated (90%) or pristine HC (83%) in half-cell configurations. More importantly, AS3iB using presodiated HC and NaCrO2 as the anode and cathode, respectively, exhibits a high ICE of 92% and an initial discharge energy density of 294 Wh kg_cathode^(-1