SiO₂‐Enhanced Structural Stability and Strong Adhesion with a New Binder of Konjac Glucomannan Enables Stable Cycling of Silicon Anodes for Lithium‐Ion Batteries

Abstract

Silicon‐based anodes with high theoretical capacity have intriguing potential applications for next‐generation high‐energy lithium‐ion batteries, but suffer from huge volumetric change that causes pulverization of electrodes. Rational design and construction of effective electrode structures combined with versatile binders remain a significant challenge. Here, a unique natural binder of konjac glucomannan (KGM) is developed and an amorphous protective layer of SiO2 is fabricated on the surface of Si nanoparticles (Si@SiO2) to enhance the adhesion. Benefiting from a plethora of hydroxyl groups, the KGM binder with inherently high adhesion and superior mechanical properties provides abundant contact sites to active materials. Molecular mechanics simulations and experimental results demonstrate that the enhanced adhesion between KGM and Si@SiO2 can bond the particles tightly to form a robust electrode. In addition to bridging KGM molecules, the SiO2‐functionalized surface may serve as a buffer layer to alleviate the stresses of Si nanoparticles resulting from the volume change. The as‐fabricated KGM/Si@SiO2 electrode exhibits outstanding structural stability upon long‐term cycles. A highly reversible capacity of 1278 mAh g−1 can be achieved over 1000 cycles at a current density of 2 A g−1, and the capacity decay is as small as 0.056% per cycle.

Engineering of Oxygen Vacancy and Electric‐Field Effect by Encapsulating Lithium Titanate in Reduced Graphene Oxide for Superior Lithium Ion Storage

“…The FTIR spectra of CTAB, TiOSO 4 , and the mixture of CTAB@TiOSO 4 exhibit typical absorption features of CTAB and TiOSO 4 (Figure S1, Supporting Information). It is worth noting that the O‐H stretching vibrations peak of CTAB@TiOSO 4 (3344 cm −1 ) has the highest intensity, and is distinctly red‐shifted compared to the pure TiOSO 4 (3393 cm −1 ), demonstrating a strong hydrogen‐bonding interaction between CTAB and oxygen‐containing groups (TiO 2+ ) . More importantly, to shed light on the interaction between TiO 2+ and CTAB, quantum chemistry calculation was performed with DFT method of MN15 in combination with the basis set of 6–31G(d) for C, H, and O atoms, and LanL2DZ for Ti atom.…”

A Facile Strategy to Construct Silver‐Modified, ZnO‐Incorporated and Carbon‐Coated Silicon/Porous‐Carbon Nanofibers with Enhanced Lithium Storage

“…The power and energy densities of lithium ion batteries (LIBs) have been increasingly demanded by the electrical equipment including intelligent robots, portable electronics, and electric vehicles . In this regard, numerous anode materials have been extensively developed to replace the commercial graphite with limited theoretical capacity of 372 mA h g −1 . Among them, Si‐based materials have received considerable attention due to their superior features in terms of natural abundance, nontoxicity, low working potential, and the highest theoretical capacity of 4200 mA h g −1 .…”

Collaborative Design of Hollow Nanocubes, In Situ Cross‐Linked Binder, and Amorphous Void@SiOx@C as a Three‐Pronged Strategy for Ultrastable Lithium Storage

“…In addition, for mass production, the preparation process of candidate binder should be simple, and its price needs to be inexpensive. In recent years, many new polymeric binders with superior properties have been explored for Si‐based anodes, including synthetic polymers such as PAA‐PVA gel binder, polyrotaxane with PAA, and PAA‐carboxymethyl cellulose, and biopolymer binder such as konjac glucomannan and gum arabic, and conductive polyer binders such as poly(3,4‐ethylenedioxythiophene):poly‐(styrene‐4‐sulfonate)‐vinyl acetate‐acrylic, sodium poly(9,9‐bis(3‐propanoate) fluorene)‐phenanthraquinone, as well as combinations of these binders, such as guar gum/xanthan gum and guar gum/sodium alginate . These aforementioned binders can improve the electrochemical properties of electrodes to some extent, however, most of them are still hard to put into practical application at present because of the relatively complex process.…”