Elucidating the Role of Prelithiation in Si-based Anodes for Interface Stabilization

Prelithiation as a facile and effective method to compensate the lithium inventory loss in the initial cycle has progressed considerably both on anode and cathode sides. However, much less research has been devoted to the prelithiation effect on the interface stabilization for long-term cycling of Si-based anodes. An in-depth quantitative analysis of the interface that forms during the prelithiation of SiOx is presented here and the results are compared with prelithiaton of Si anodes. Local structure probe combined with detailed electrochemical analysis reveals that a characteristic mosaic interface is formed on both prelithiated SiOx and Si anodes. This mosaic interface containing multiple lithium silicates phases, is fundamentally different from the solid electrolyte interface (SEI) formed without prelithiation. The ideal conductivity and mechanical properties of lithium silicates enable improved cycling stability of both prelithiated anodes. With a higher ratio of lithium silicates due to the oxygen participation, prelithiated SiO1.3 anode improves the initial coulombic efficiency to 94% in full cell and delivers good cycling retention (77%) after 200 cycles. The insights provided in this work can be used to further optimize high Si loading (>70% by weight) based anodes in future high energy density batteries

Key Parameters in Determining the Reactivity of Lithium Metal Battery

Lithium metal anodes are crucial for high-energy-density batteries, but concerns regarding their safety remain. Limited investigations have evaluated the reactivity of Li metal anodes in full cell configurations. In this study, differential scanning calorimetry (DSC) and in situ Fourier-transform infrared spectroscopy (FTIR) were employed to quantitatively examine the Li metal reactivity. Lithiated graphite (Li-Gr) and lithiated silicon (Li-Si) were also compared. The reactivity of plated Li was systematically investigated when combined with different electrolyte compositions, morphologies, atmospheres, and various cathode materials (NMC622, LFP, and LNMO). It was discovered that all cell components, such as electrolyte composition, Li morphology, control of inactive Li accumulation, and cathode stability, play essential roles in regulating the reactivity of the plated Li. By optimizing these factors, the Li metal full cell exhibited no significant thermal reaction up to 400 °C. This research identifies key parameters for controlling Li metal reactivity, potentially advancing lithium metal battery design and manufacturing

Key Parameters in Determining the Reactivity of Lithium Metal Battery

Lithium metal anodes are crucial for high-energy-density batteries, but concerns regarding their safety remain. Limited investigations have evaluated the reactivity of Li metal anodes in full cell configurations. In this study, differential scanning calorimetry (DSC) and in situ Fourier-transform infrared spectroscopy (FTIR) were employed to quantitatively examine the Li metal reactivity. Lithiated graphite (Li-Gr) and lithiated silicon (Li-Si) were also compared. The reactivity of plated Li was systematically investigated when combined with different electrolyte compositions, morphologies, atmospheres, and various cathode materials (NMC622, LFP, and LNMO). It was discovered that all cell components, such as electrolyte composition, Li morphology, control of inactive Li accumulation, and cathode stability, play essential roles in regulating the reactivity of the plated Li. By optimizing these factors, the Li metal full cell exhibited no significant thermal reaction up to 400 °C. This research identifies key parameters for controlling Li metal reactivity, potentially advancing lithium metal battery design and manufacturing

A free-standing lithium phosphorus oxynitride thin film electrolyte promotes uniformly dense lithium metal deposition with no external pressure

Lithium phosphorus oxynitride (LiPON) is an amorphous solid electrolyte that has been extensively studied over the last three decades. Despite the promise of pairing it with various electrode materials, LiPON's rigidity and air sensitivity set limitations to understanding its intrinsic properties. Here we report a methodology to synthesize LiPON in a free-standing form that manifests remarkable flexibility and a Young's modulus of ∼33 GPa. We use solid-state nuclear magnetic resonance and differential scanning calorimetry to quantitatively reveal the chemistry of the Li/LiPON interface and the presence of a well-defined LiPON glass-transition temperature of 207 °C. Combining interfacial stress and a gold seeding layer, our free-standing LiPON shows a uniformly dense deposition of lithium metal without the aid of external pressure. This free-standing LiPON film offers opportunities to study fundamental properties of LiPON for interface engineering for solid-state batteries

Carbon Free High Loading Silicon Anodes Enabled by Sulfide Solid Electrolytes for Robust All Solid-State Batteries

The development of silicon anodes to replace conventional graphite in efforts to increase energy densities of lithium-ion batteries has been largely impeded by poor interfacial stability against liquid electrolytes. Here, stable operation of 99.9 weight% micro-Si (uSi) anode is enabled by utilizing the interface passivating properties of sulfide based solid-electrolytes. Bulk to surface characterization, as well as quantification of interfacial components showed that such an approach eliminates continuous interfacial growth and irreversible lithium losses. In uSi || layered-oxide full cells, high current densities at room temperature (5 mA cm 2), wide operating temperature (-20{\deg}C to 80{\deg}C) and high loadings (>11 mAh cm-2) were demonstrated for both charge and discharge operations. The promising battery performance can be attributed to both the desirable interfacial property between uSi and sulfide electrolytes, as well as the unique chemo-mechanical behavior of the Li-Si alloys

Carbon Free High Loading Silicon Anodes Enabled by Sulfide Solid Electrolytes for Robust All Solid-State Batteries

The development of silicon anodes to replace conventional graphite in efforts to increase energy densities of lithium-ion batteries has been largely impeded by poor interfacial stability against liquid electrolytes. Here, stable operation of 99.9 weight% micro-Si (uSi) anode is enabled by utilizing the interface passivating properties of sulfide based solid-electrolytes. Bulk to surface characterization, as well as quantification of interfacial components showed that such an approach eliminates continuous interfacial growth and irreversible lithium losses. In uSi || layered-oxide full cells, high current densities at room temperature (5 mA cm 2), wide operating temperature (-20{\deg}C to 80{\deg}C) and high loadings (>11 mAh cm-2) were demonstrated for both charge and discharge operations. The promising battery performance can be attributed to both the desirable interfacial property between uSi and sulfide electrolytes, as well as the unique chemo-mechanical behavior of the Li-Si alloys

A 5V-class Cobalt-free Battery Cathode with High Loading Enabled by Dry Coating

Transitioning toward more sustainable materials and manufacturing methods will be critical to continue supporting the rapidly expanding market for lithium-ion batteries. Meanwhile, energy storage applications are demanding higher power and energy densities than ever before, with aggressive performance targets like fast charging and greatly extended operating ranges and durations. Due to its high operating voltage and cobalt-free chemistry, the spinel-type LiNi0.5Mn1.5O4 (LNMO) cathode material has attracted great interest as one of the few next-generation candidates capable of addressing this combination of challenges. However, severe capacity degradation and poor interphase stability have thus far impeded the practical application of LNMO. In this study, by leveraging a dry electrode coating process, we demonstrate LNMO electrodes with stable full cell operation (up to 68% after 1000 cycles) and ultra-high loading (up to 9.5 mAh/cm2 in half cells). This excellent cycling stability is ascribed to a stable cathode-electrolyte interphase, a highly distributed and interconnected electronic percolation network, and robust mechanical properties. High-quality images collected using plasma focused ion beam scanning electron microscopy (PFIB-SEM) provide additional insight into this behavior, with a complementary 2-D model illustrating how the electronic percolation network in the dry-coated electrodes more efficiently supports homogeneous electrochemical reaction pathways. These results strongly motivate that LNMO as a high voltage cobalt-free cathode chemistry combined with an energy-efficient dry electrode coating process opens the possibility for sustainable electrode manufacturing of cost-effective and high-energy-density cathode materials

Carbon-free high-loading silicon anodes enabled by sulfide solid electrolytes.

The development of silicon anodes for lithium-ion batteries has been largely impeded by poor interfacial stability against liquid electrolytes. Here, we enabled the stable operation of a 99.9 weight % microsilicon anode by using the interface passivating properties of sulfide solid electrolytes. Bulk and surface characterization, and quantification of interfacial components, showed that such an approach eliminates continuous interfacial growth and irreversible lithium losses. Microsilicon full cells were assembled and found to achieve high areal current density, wide operating temperature range, and high areal loadings for the different cells. The promising performance can be attributed to both the desirable interfacial property between microsilicon and sulfide electrolytes and the distinctive chemomechanical behavior of the lithium-silicon alloy