Electrode-level strategies enabling kinetics-controlled metallic Li confinement by the heterogeneity of interfacial activity and porosity

Three-dimensional (3D) host architectures have emerged as promising strategies for resolving the critical issues of Li metal anodes, namely, severe volume changes and growth of Li dendrites during battery cycling. However, preferential Li plating on top of the host architecture often causes early cell failure. Herein, we demonstrate that the controlled heterogeneity of interfacial activity and the porous structure at the electrode level enables confined Li metal storage in host architectures consisting of metal-organic framework (MOF)-derived carbon. 3D electrochemical simulations show that carbon activity (lithiophilicity) and interparticle porosity play critical roles in controlling the competing kinetics of charge transfer and Li+ transport, thereby regulating the Li-plating behavior. The enhanced lithiophilicity at the electrode bottom, combined with the increased interparticle porosity at the top, is predicted to promote the preferential nucleation of Li and subsequent upward growth from the bottom. Based on the proposed design principles, high-capacity and long-cycling host architectures based on MOF-derived carbon are constructed via two-step electrophoretic deposition (EPD): densely populated Ag-incorporated carbon at the bottom in combination with sparsely populated Ag-free carbon at the top. The heterogeneous host architecture fabricated by EPD spatially confines a large amount of Li metal (6 mAh cm–2) without significant volume changes and exhibits a long cycle lifetime of over 900 cycles. This study provides an effective strategy for designing advanced Li metal anodes by controlling the competing reaction kinetics in 3D host architectures

Enhancing Bifunctional Catalytic Activity via a Nanostructured La(Sr)Fe(Co)O_3−δ@Pd Matrix as an Efficient Electrocatalyst for Li–O₂ Batteries

One of the important challenges with a bifunctional electrocatalyst is reducing the large overpotential involved in the slow kinetics of the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) at the air electrode in a metal–air redox battery. Here, we present a nanostructured LSCF@Pd matrix of nanostructured LSCF (Nano-LSCF) with palladium to enhance the bifunctional catalytic activity in Li–O2 battery applications. Pd nanoparticles can be perfectly supported on the surface of the Nano-LSCF, and the ORR catalytic activity was properly improved. When Nano-LSCF@Pd was applied to a cathode catalyst in Li–O2 batteries, the first discharge ability (16912 mA h g–1) was higher than that of Nano-LSCF (6707 mA h g–1) and the cycling property improved. These results demonstrate that the Pd-deposited nanostructured perovskite is a capable catalyst to enhance the ORR activity of LSCF as a promising bifunctional electrocatalyst

Mechanistic and nanoarchitectonics insight into Li–host interactions in carbon hosts for reversible Li metal storage

Li metal has been regarded as a promising anode for rechargeable batteries with high energy densities. However, the growth of Li dendrites and severe volume changes in the Li anode still hinder its practical use. Three-dimensional (3D) host structures have recently attracted significant attention as an effective strategy to resolving these problems. Herein, we demonstrate reversible Li metal storage in carbon hosts with strong Li–host interactions derived from metal-organic frameworks (MOFs). The combined experimental and computational modeling studies reveal that galvanically displaced Ag enhances Li–host interactions and the spatial distribution characteristics of Ag play a crucial role in controlling Li storage behavior and reversibility. The atomic Ag clusters trigger the outward growth of Li from the internal pores of the host and enables stable battery cycling, whereas the surface-anchored Ag nanoparticles induce uneven Li plating on the outer surface of the carbon host, resulting in a rapid performance drop. This work provides new insights into the development of advanced host materials for reversible Li anodes by utilizing strong Li–host interactions

Critical role of surface craters for improving the reversibility of Li metal storage in porous carbon frameworks

Recently, a certain type of porous carbon framework (PCF) based on zeolitic imidazolate frameworks (ZIFs) has been proposed as a promising anode material for metallic Li storage owing to its controllable pore structure and functionality. With the purpose of improving the Li storage capability and reversibility, meso-scale surface craters (SCs) are strategically introduced on the outermost surface of the PCF via hard templating with colloidal SiO2 nanoparticles. Combined structural and electrochemical investigations demonstrate the critical role of SCs in improving the reversibility of PCF in repeated Li plating and stripping. The SCs on the PCF surface provide facile pathways for the transport of Li ions through the electrode, promote Li plating in the internal pores, and serve as meso-scale sites for metallic Li storage. Furthermore, an SC-integrated PCF anode has shown improved rate capability and cycling performance in a full-cell configured with a commercial cathode, when compared to the conventional PCF anode. This work could offer practical guidelines for the development of robust Li storage materials for advanced Li-metal batteries