Rational Design of Robust and Universal Aqueous Binders to Enable Highly Stable Cyclability of High‐Capacity Conversion and Alloy‐Type Anodes

Abstract

The development of high‐performance binders is a simple but effective approach to address the rapid capacity decay of high‐capacity anodes caused by large volume change upon lithiation/delithiation. Herein, we demonstrate a unique organic/inorganic hybrid binder system that enables an efficient in situ crosslinking of aqueous binders (e.g., sodium alginate (SA) and carboxymethyl cellulose (CMC)) by reacting with an inorganic crosslinker (sodium metaborate hydrate (SMH)) upon vacuum drying. The resultant 3D interconnected networks endow the binders with strong adhesion and outstanding self‐healing capability, which effectively improve the electrode integrity by preventing fracturing and exfoliation during cycling and facilitate Li+ ion transfer. SiO anodes fabricated from the commercial microsized powders with the SA/0.2SMH binder maintain 1470 mAh g−1 of specific capacity at 100 mA g−1 after 200 cycles, which is 5 times higher than that fabricated with SA binder alone (293 mAh g−1). Nearly, no capacity loss was observed over 500 cycles when limiting discharge capacity at 1500 mAh g−1. The new binders also dramatically improved the performance of Fe2O3, Fe3O4, NiO, and Si electrodes, indicating the excellent applicability. This finding represents a novel strategy in developing high‐performance aqueous binders and improves the prospect of using high‐capacity anode materials in Li‐ion batteries.

Polymeric Binders Used in Lithium Ion Batteries: Actualities, Strategies and Trends

“…Yao et al [108] . constructed organic‐inorganic hybrid polymer binder (SA‐SMH) by in‐situ crosslinking reaction between the borate in sodium metaborate hydrate tetrahydrate (NaBO 2 ⋅ 4H 2 O) and −OH in sodium alginate (SA).…”

“…Common are chitosan (CS), sodium alginate (SA), starch, and some other uncommon natural polysaccharides. [102][103][104][105][106][107] Yao et al [108] constructed organic-inorganic hybrid polymer binder (SA-SMH) by in-situ crosslinking reaction between the borate in sodium metaborate hydrate tetrahydrate (NaBO 2 • 4H 2 O) and À OH in sodium alginate (SA). SA-SMH with 3D interconnect network structure, has strong adhesion and self-healing ability, and effectively improves the integrity of SiO (~1-10 μm) electrodes (Active material : Conductive material : Binder = 7 : 2 : 1), and long-term circulation ability of battery.…”

L-Cysteine Cross-Linked Sodium Alginate as a Binder with Strong Binding Force on Copper Foils To Enhance Sodium Storage Performance

“…Additionally, common water-based binders struggle to effectively bond electrode materials to the current collector, leading to the detachment of electrode materials and a rapid decline in cycling stability. To address these issues, researchers have developed SA-based (three-dimensional) 3D network cross-linked binders, such as SA-ion cross-linked binders, − SA-inorganic cross-linked binders, , and SA-organic cross-linked binders . The use of these cross-linked binders helps to maintain the stability of electrode materials.…”

A Robust Network Sodium Carboxymethyl Cellulose-Epichlorohydrin Binder for Silicon Anodes in Lithium-Ion Batteries

“…3 Furthermore, the employment of N-methyl pyrrolidone (NMP) solvent, utilized as a dispersant in PVDF, poses environmental concerns and presents challenges in safe removal during battery disposal and recycling during battery disposal and recycling. 13 Inspired by natural polysaccharides, some water-soluble biobased polymers are extensively employed as binders in electrodes to improve the electrochemical performance of the Si anodes due to being rich in polar groups of −OH, −NH 2 , and −COOH, such as carboxymethyl cellulose (CMC), 14 guar gum (GG), 1 and poly(acrylic acid) (PAA). 15 However, it is difficult for these linear binders to meet the requirements of strong adhesion through the line-to-point bonding mode, especially in the face of Si anodes with huge volume changes.…”

“…To solve this issue, direct bond formation by cross-linking seems to be more preferred by researchers. A series of cross-linked binder systems were reported, such as PAA-Lys, 16 PGA-ECH, 17 CMC-PDA, 18 SH-ECH, 19 PG-ECH, 11 SA-SMH, 13 and SA-SB, 20 all of which have shown a strong bonding effect and effectively buffer larger volume changes of Si anodes. In this study, the small molecule epichlorohydrin (ECH) was used to cross-link CMC by a simple epoxy ring-opening reaction to form a robust 3D network-structured binder with abundant polar hydroxyl and carboxyl groups.…”