Silicon anodes are promising for high energy batteries because of their excellent theoretical gravimetric capacity (3579 mA h g-1). However, silicon's large volume expansion and poor conductivity hinder its practical application; thus, binders and conductive additives are added, effectively diluting the active silicon material. To address this issue, reports of 2D MXene nanosheets have emerged as additives for silicon anodes, but many of these reports use high MXene compositions of 22-66 wt%, still presenting the issue of diluting the active silicon material. Herein, this report examines the question of what minimal amount of MXene nanosheets is required to act as an effective additive while maximizing total silicon anode capacity. A minimal amount of only 4 wt% MXenes (with 16 wt% sodium alginate and no carbon added) yielded silicon anodes with a capacity of 900 mA h gSi-1 or 720 mA h gtotal-1 at the 200th cycle at 0.5 C-rate. Further, this approach yielded the highest specific energy on a total electrode mass basis (3100 W h kgtotal-1) as comapared to other silicon-MXene constructs (∼115-2000 Wh kgtotal-1) at a corresponding specific power. The stable electrode performance even with a minimal MXene content is attributed to several factors: (1) highly uniform silicon electrodes due to the dispersibility of MXenes in water, (2) the high MXene aspect ratio that enables improved electrical connections, and (3) hydrogen bonding among MXenes, sodium alginate, and silicon particles. All together, a much higher silicon loading (80 wt%) is attained with a lower MXene loading, which then maximizes the capacity of the entire electrode.
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January 2025
School of Energy Science and Engineering and Jiangsu Key Laboratory of Process Enhancement and New Energy Equipment Technology, Nanjing Tech University, Nanjing, Jiangsu Province, 211816, China.
The application of micro-nano size photovoltaic waste silicon (wSi) as an anode material for lithium-ion battery holds significant practical potential; However, it faces a series of challenges related to the volume expansion of Si during cycling. In this study, a simple, efficient, and eco-friendly microwave method is proposed for the rapid preparation of graphene-coated silicon materials (wSi@rGO) in just a few seconds, in which graphene as the stable interface mitigates structural failure caused by significant volume expansion, enhances electron and ion conductivity, inhibits undesirable side reactions between silicon and electrolyte, and promotes the stability of solid electrolyte interface (SEI). Importantly, the instantaneous high temperature generated by microwaves facilitates the formation of interfacial SiC chemical bonds, which strengthen the interaction between Si and graphene, thereby reducing Si delamination.
View Article and Find Full Text PDFNanoscale
January 2025
Advanced Batteries Research Center, Korea Electronics Technology Institute, 25, Saenari-ro, Seongnam-si, 13509, Republic of Korea.
The SiO electrode interface is passivated with a SiO layer, which hinders the deposition of an inorganic solid electrolyte interphase (SEI) due to its high surface work function and low exchange current density of electrolyte decomposition. Consequently, a thermally vulnerable, organic-based SEI formed on the SiO electrode, leading to poor cycling performance at elevated temperatures. To address this issue, the SEI formation process is thermoelectrochemically activated.
View Article and Find Full Text PDFACS Omega
January 2025
Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112-0114, United States.
Silicon (Si) is recognized as a promising anode material for lithium-ion batteries (LIBs). However, the significant volume expansion during lithiation poses a make-or-break challenge for the commercial adoption of silicon as an anode. The solutions to mitigate the challenge often depend on processes that can increase costs for the LIB.
View Article and Find Full Text PDFNat Commun
January 2025
State Key Laboratory of Silicon and Advanced Semiconductor Materials, Department of Polymer Science and Engineering, International Research Center for X Polymers, Zhejiang University, Hangzhou, PR China.
The interfacial molecular dipole enhances the photovoltaic performance of perovskite solar cells (PSCs) by facilitating improved charge extraction. However, conventional self-assembled monolayers (SAMs) face challenges like inadequate interface coverage and weak dipole interactions. Herein, we develop a strategy using a self-assembled ferroelectric layer to modify the interfacial properties of PSCs.
View Article and Find Full Text PDFThis paper explores the process of forming arrays of vertically oriented carbon nanotubes (CNTs) localized on metal electrodes using thin porous anodic alumina (PAA) on a solid substrate. On a silicon substrate, a titanium film served as the electrode layer, and an aluminium film served as the base layer in the initial film structure. A PAA template was formed from the Al film using two-step electrochemical anodizing.
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