This study presents a streamlined fabrication process for lithium-ion battery (LIB) electrodes, involving the dispersion of carbon nanotubes (CNT), silicon (Si), and graphene oxide (GO) in an aqueous solution, followed by vacuum filtration to produce self-standing composite electrodes. Two reduction routes are employed to form reduced graphene oxide (rGO). The chemically reduced CNT/Si/rGO-5%-Chem anode exhibits superior mechanical resilience compared to thermally reduced counterparts, which suffer from reduced strength and structural integrity. Chemical reduction also enhances electrochemical performance, increasing the initial capacity of the non-reduced CNT/Si/GO-5% composite anode from 1,461 to 2,342 mAh g−1, with improved long-term cycling performance. Electrochemical impedance spectroscopy shows lower pre-cycle charge transfer resistance (148 Ω) and superior solid electrolyte interphase (SEI) resistance (43 Ω) for chemically reduced anodes compared to thermally reduced ones. After cycling, the chemically reduced composite anode exhibits reduced electrolyte resistance and charge transfer resistance, indicating stable electrochemical reactions. The composite structure undergoes adaptive rearrangements during cycling, optimizing active material utilization. In summary, CNTs accommodate silicon swelling, while chemically reduced rGO promotes stable SEI formation, highlighting the benefits of chemical reduction in enhancing mechanical durability and electrochemical performance, making the self-standing CNT/Si/rGO composite film a promising LIB anode.
The main motivation for replacing lithium-ion batteries with lithium metal batteries is to achieve a higher energy density by using the metallic lithium anode. One of the major challenges with rechargeable lithium metal batteries is the formation of lithium dendrites and dead lithium during repeated cycling. Another challenge is the formation of the unstable solid electrolyte interphase (SEI) on the surface of the lithium metal electrode, which can reduce battery efficiency and cycle life. In the present work, two different lithium silicates (Li2Si2O5 and Li2SiO3) are successfully synthesized and implemented as an artificial SEI layer via a simple dry coating method. The lithium silicate coating acts as a protective barrier that prevents direct contact between the lithium metal and the electrolyte, which can cause undesirable side reactions and reduce the efficiency and lifetime of the battery. The lithium silicate artificial SEI layer improves the stability of lithium metal batteries by reducing unwanted surface reactions, optimizing ion transport kinetics, and protecting the lithium metal anode from mechanical deformation and unstable SEI formation during extended cycling. This laminated lithium anode structure can be an effective design for the future development of rechargeable lithium metal batteries.
Lithium-ion batteries (LIBs) and electrical double-layer capacitors (EDLCs) are widely used in commercial energy storage systems, but each has inherent limitations. To overcome these limitations, the lithium-ion capacitor (LIC) has emerged as a hybrid energy storage device, combining the benefits of LIBs and EDLCs. However, the introduction of active lithium into LICs poses challenges due to lithium's reactivity and instability. In this study, we propose a dual wet chemical prelithiation strategy to enhance LIC performance. By wet chemically prelithiating both the activated carbon cathodes and hard carbon anodes, significant improvements are achieved compared to traditional prelithiation methods. The dual prelithiation approach outperforms electrochemical prelithiation in terms of energy storage performance, cycle life, and process simplification. LICs with dual wet chemically prelithiated electrodes demonstrate the highest energy density and retain a substantial portion of reversible capacity even at high discharge rates. The strategy exhibits fast kinetics and wide operational stability. In contrast, LICs with metallic lithium anodes or electrochemically prelithiated hard carbon anodes exhibit inferior performance and limited cycle life. The dual wet chemical prelithiation strategy represents a breakthrough in LIC technology, offering superior performance, cycle stability, and scalability. It holds promise for alkali-ion energy storage systems and drives advancements in electrochemical energy storage technology.
