Engineering Prelithiation of Polyacrylic Acid Binder: A Universal Strategy to Boost Initial Coulombic Efficiency for High‐Areal‐Capacity Si‐Based Anodes

Abstract

The low initial Coulombic efficiency (ICE) and insufficient cycling lives of silicon (Si)‐based anodes seriously hinder their eventual introduction into next‐generation high‐energy‐density lithium–ion batteries (LIBs). Herein, an engineering prelithiation binder strategy based on polyacrylic acid (LixPAA) is proposed for representative SiOx anodes. The ICEs and cycling lives of SiOx anodes are significantly improved by precisely controlling the lithiation degree of PAA binder. The ICE of the high‐loading (3.0 mg cm−2) SiOx electrode increases by 10.9% when the Li0.75PAA binder replaces the PAA binder. Moreover, the working mechanism of the lithiation binder strategy to improve the electrochemical performances (especially for ICE) is systematically investigated, which is universally applied to other Si anodes such as Si nanoparticles and Si/graphite. This universal binder strategy and proposed working mechanism provide enlightenment on constructing high‐ICE, high‐energy‐density, and long‐life Si‐based anodes.

Vanadium-Tailored Silicon Composite with Furthered Ion Diffusion Behaviors for Longevity Lithium-Ion Storage

“…Whereas, the theoretical specific capacity of graphite is only 372 mAh g –1 , which is unable to match the growing demand for higher-energy-density LIBs in today’s world. − Under such a premise, a series of anode materials with higher theoretical specific capacity gradually come into view. Particularly, silicon has a high theoretical capacity (3579 mAh g –1 ), low reacting voltage (0.1–0.4 V), and abundant resource storage (26.4%), becoming one of the alternative anodes with great potential in the future. − Yet now, the commercial promotion of silicon-based anodes in the field of LIBs is extremely difficult and hindered by the following aspects. First of all, silicon is a typical semiconductor with poor conductivity and slower electron transport.…”

In Situ Preparation of High-Performance Silicon-Based Integrated Electrodes Using Cross-Linked Cyclodextrins

“…These binders exhibit favorable adhesion and potential self-healing function in the industrial production of batteries. In addition, composite binders cross-linked with other binders or modified by metal ions, such as Li x PAA, PFA-TPU, etc., also have significant achievements in enhancing the performance of silicon-based negative electrodes. In the study of Wu et al, “Hard” poly­(furfuryl alcohol) (PFA) and “soft” thermoplastic polyurethane (TPU) are interweaved into 3D conformation to confine SiO x particles via in situ polymerization .…”

Three-Dimensional Crosslinked PAA-TA Hybrid Binders for Long-Cycle-Life SiOx Anodes in Lithium-Ion Batteries

“…High-capacity electrode materials are generally recognized as the key for achieving high energy density in lithium-ion batteries (LIBs). − Among them, SiO x have been considered as ideal candidates because of their higher specific capacity relative to graphite and smaller volume change compared with pure silicon. − However, a large volume expansion (118%), poor electronic conductivity, and low initial coulomb efficiency (ICE) hinder their practical application. , Numerous design strategies have been explored to solve these inherent disadvantages, such as core–shell structures, , size refinement, and carbon coating. ,, However, the synthesis of modified silicon-based materials often involves high cost and complex fabrication processes . Binders, as essential components with a simple preparation process and low cost, offer an effective adhesive network to keep active materials and conductive agents on the current collectors, retaining the structural integrity of electrodes. − Nevertheless, conventional binders including poly­(vinylidene fluoride) (PVDF) and carboxymethylcellulose (CMC) fail to provide sufficient adhesion and mechanical properties for suppressing the severe volume expansion of silicon-based anodes due to the comparatively weak interactions. − …”