3D SnO₂/Graphene Hydrogel Anode Material for Lithium-Ion Battery

Abstract

With the widespread use of mobile electronic devices and increasing demand for electric energy storage in the transportation and energy sectors, lithium-ion batteries (LIBs) have become a major research and development focus in recent years. The current generation of LIBs use graphite as the anode material, which has a theoretical capacity of 372 mAh•g -1 . Tin-based materials are considered promising anode materials for next-generation LIBs because of their favorable working voltage and unsurpassed theoretical specific capacity. However, overcoming the rapid storage capacity degradation of tin caused by its large volumetric changes (> 200%) during cycling remains a major challenge to the successful implementation of such materials. In this paper, SnO2 nanoparticles with a diameter of 2-3 nm were used as active materials in LIB anodes and a threedimensional (3D) graphene hydrogel (GH) was used as a buffer to decrease the volumetric change. Typically, SnCl4 aqueous solution (18 mL, 6.4 mmol•L -1 ) and graphene oxide (GO) suspension (0.5% (w, mass fraction), 2 mL) were mixed together via sonication. NaOH aqueous solution (11.4 mmol•L -1 , 40 mL) was slowly added and then the mixture was stirred for 2 h to obtain a stable suspension. Vitamin C (VC, 80 mg) was then added as a reductant. The mixture was kept at 80°C for 24 h to reduce and self-assemble. The resulting black block was washed repeatedly with distilled deionized water and freeze-dried to obtain SnO2-GH. In this composite, GH provides large specific surface area for efficient loading (54% (w)) and uniform distribution of nanoparticles. SnO2-GH delivered a capacity of 500 mAh•g -1 at 5000 mA•g -1 and 865 mAh•g -1 at 50 mA•g -1 after rate cycling.

Unveiling the Complex Redox Reactions of SnO2 in Li-Ion Batteries Using Operando X-ray Photoelectron Spectroscopy and In Situ X-ray Absorption Spectroscopy

“…Conversion-alloying materials are promising choices, owing to their high specific charge, 3–4 times higher than the current commercial graphite (372 mAh/g) anode. − However, multiple challenges need to be solved before their introduction into commercial cells. Among them is the high volume expansion during lithiation, leading to cracking of the particles and crumbling of the electrode. − Another important challenge is related to the fundamental understanding of their complex redox reactions, the identification of the various compounds generated and/or consumed, and the reversibility of the reactions during the repeated lithiation and delithiation cycles. A full understanding of the reaction mechanisms is a necessary first step to minimizing the overpotentials in future practical battery electrodes for faster charging.…”

Hollow Porous CoSnOx Nanocubes Encapsulated in One-Dimensional N-Doped Carbon Nanofibers as Anode Material for High-Performance Lithium Storage

“…Compared to other rechargeable batteries, lithium-ion batteries (LIB) have a clear dominance and have been applied in various fields because of their unique advantages embodied in low self-discharge, high energy density, large output voltage, and no memory effect. − It appears to create great interest in finding long-life and high-performance electrode materials, especially anode materials. Tin-based materials have been considered as one of the most competitive candidates among the many available anode materials due to high specific capacity (994 mAh g –1 ), which is much more than that of the commercial graphite (372 mAh g –1 ), suitable potential platform, and flexible selectivity. − However, tin-based metal oxides suffer from huge volume change during lithiation/delithiation, resulting from the unique lithium storage mechanism of the reversible reaction between Sn and Li x Sn alloy after the initial irreversible reduction of SnO x . − Most significantly, the pulverization of anode materials leads to the aggregation of active particles and continuous formation of a solid electrolyte interface (SEI), which eventually results in reduced conductivity and fast capacity fading. , …”

Three-Dimensional Graphene-Based Pt-Cu Nanoparticles-Containing Composite as Highly Active and Recyclable Catalyst

“…Carbon-supported noble metal nanoparticles (NPs) have rapid development with wide applications in the field of catalysis, storage and energy conversion, and biomedicine 1,2 . As an important member of the carbon family, graphene have a variety of applications in catalysis and energy conversion and storage 3 because of their unique 2D structures and excellent properties.…”