Exploiting the capacity merits of Si anodes in the energy-dense prototypes via a homogeneous prelithiation therapy. (May 2022) - Wang, Helin
Abstract: The practical exploitation of the high-capacity Si anodes suffers from the insufficient cation utilization degree in the energy-dense batteries, which originates from unstable interfacial dynamics, lithiation-induced mechanical stress, and irreversible Li trapping in the alloy intermediates. Herein, we develop a scalable, indirect mechanical calendaring approach to enable the homogeneous prelithiation process, specifically through interpolating an intermediate buffer layer (IBL) with tunable electronic/ionic pathways in-between the lithium foil source and the target high-capacity electrode. Upon the prototype assembly of various prelithiated Si/Graphite anodes (450–1000 mAh g −1 at the constant areal capacity of 4.6 mAh cm −2 ) and the LiNi0.8 Co0.1 Mn0.1 O2 cathode (NCM811, 23 mg cm −2 for the double-sided electrode), the enhanced Li utilization degree with the highest energy density up to 362 Wh kg −1 could be achieved on the realistic cell level (1.6 Ah pouch model). More encouragingly, the reversible phasic evolution of both the cathode and anode, upon the Li + inventory replenishment, are real-time tracked by the transmission-mode operando X-ray diffraction (XRD). This IBL-regulated approach is further extended to construct an environmental-adaptive composite film that integrates the metallic Li source, the prelithiation of which could well function even at the extreme humid conditions (long-time shelf life or relative humidity up to 85%). Graphical Abstract: Si-based anodes have been largely impeded by the loss of Li + inventory due to SEI growth and irreversibly trapped Li-Si alloy. In this work, Wang et al. develop a prelithiation approach by interpolating an intermediate buffer layer (IBL) with controlled dimensional specification in-between the metallic lithium source and the Si/G composite anodes, enabling customized prelithiation and homogeneous Li + replenishment. The dynamic phasic tracking reveals the crucial influence of the IBL-regulated prelithiation process on the Li utilization degree. ga1 Highlights: Benefitting from tailored dimensional features and ionic diffusivities of the IBL, the versatile prelithiation approach could be applied to various anodes. Transmission-mode operando XRD provides a real-time methodology to document the phasic transitions of both cathode and anode. An environmental-adaptive Li-IBL was constructed, and the prelithiation of which could well function even at the extreme conditions.