Ion- and Electron-Conductive Buffering Layer-Modified Si Film for Use as a High-Rate Long-Term Lithium-Ion Battery Anode

Improving Electrochemical Performance of Thick Silicon Film Anodes with Implanted Solid Lithium Source Electrolyte

Silicon is a potential next-generation anode material for a lithium-ion battery. However, the large-scale application of silicon is restricted by poor electrical conductivity, large volume change, and high irreversible capacity during the charge/discharge process. Here, we proposed a simple strategy by preimplanting a solid lithium source electrolyte (Li₂CO₃ and Li₂O) into Si thick film to improve the electrochemical properties of Si materials. The implanted solid lithium source electrolyte participates in and induces the formation of SEI not only on the top surface of Si film but also in the interface of Si particles. The thick Si film with the implanted solid lithium electrolyte (a thickness of ∼10 μm) delivers above 2000 mAh g^-1 specific capacity, >92% initial Coulombic efficiency, and ∼87% capacity retention over 150 cycles at 400 mA g^-1. The present work sheds light on the design of high capacity and long cycle life electrode materials for other batteries.

Recent Advances in Silicon-Based Electrodes: From Fundamental Research toward Practical Applications

The increasing demand for higher-energy-density batteries driven by advancements in electric vehicles, hybrid electric vehicles, and portable electronic devices necessitates the development of alternative anode materials with a specific capacity beyond that of traditional graphite anodes. Here, the state-of-the-art developments made in the rational design of Si-based electrodes and their progression toward practical application are presented. First, a comprehensive overview of fundamental electrochemistry and selected critical challenges is given, including their large volume expansion, unstable solid electrolyte interface (SEI) growth, low initial Coulombic efficiency, low areal capacity, and safety issues. Second, the principles of potential solutions including nanoarchitectured construction, surface/interface engineering, novel binder and electrolyte design, and designing the whole electrode for stability are discussed in detail. Third, applications for Si-based anodes beyond LIBs are highlighted, specifically noting their promise in configurations of Li-S batteries and all-solid-state batteries. Fourth, the electrochemical reaction process, structural evolution, and degradation mechanisms are systematically investigated by advanced in situ and operando characterizations. Finally, the future trends and perspectives with an emphasis on commercialization of Si-based electrodes are provided. Si-based anode materials will be key in helping keep up with the demands for higher energy density in the coming decades.

Planar Fully Stretchable Lithium-Ion Batteries Based on a Lamellar Conductive Elastomer

Stretchable lithium-ion batteries (LIBs) have attracted great attention as a promising power source in the emerging field of wearable electronics. Despite the recent advances in stretchable electrodes, separators, and sealing materials, building stretchable full batteries remains a big challenge. Herein, a simple strategy to prepare stretchable electrodes and separators at the full battery scale is reported. Then, electrostatic spraying is used to make the anode and cathode on an elastic current collector. Finally, a polyvinylidene fluoride/thermoplastic polyurethane nanofiber separator is hot-sandwiched between the cathode and anode. The fabricated battery shows stable electrochemical performance during repeatable release-stretch cycles. In particular, a stable capacity of 6 mA•h/cm² at the current rate of 0.5 C can be achieved for the fully stretchable LIB. More importantly, over 70% of the initial capacity can be maintained after 100 cycles with ∼150% stretch.