Hierarchical goethite nanoparticle and tin dioxide quantum dot anchored on reduced graphene oxide for long life and high rate lithium-ion storage

The synergetic effect between two or more electrochemically active materials usually leads to superior lithium-ion storage performance. This work demonstrates a straightforward and effective approach to synthesize a reduced graphene oxide (RGO) encapsulated larger goethite (FeOOH) nanoparticles and smaller tin dioxide (SnO₂) quantum dots hierarchical composite (SnO₂@FeOOH/RGO). The synthesized SnO₂@FeOOH/RGO composite exhibits encouraging lithium-ion storage capability than controlled SnO₂/RGO and FeOOH/RGO samples with a stable specific capacity of 638 mAh·g^-1 under a high current rate of 1000 mA·g^-1 for 2000 continual cycles and good rate performance. The redox reaction between reductive metal-atoms or metal-ions and graphene oxide (GO) sheets guarantees an effective immobilization of corresponding nano-sized metal oxide and hydroxide crystals by the RGO framework. Furthermore, the engineered larger FeOOH crystals engage in lithium-ion storage and perform an ideal spacer between the restacked RGO sheets. Therefore, smaller SnO₂ quantum dots' inherent excellent rate capability is extensively promoted due to the improvement of electrolyte diffusion and electron transfer condition. The sample design and fabrication method in this work might be developed for broader applications.

Solvent-Free Synthesis of Uniform MOF Shell-Derived Carbon Confined SnO2 /Co Nanocubes for Highly Reversible Lithium Storage

Tin dioxide (SnO₂ ) has attracted much attention in lithium-ion batteries (LIBs) due to its abundant source, low cost, and high theoretical capacity. However, the large volume variation, irreversible conversion reaction limit its further practical application in next-generation LIBs. Here, a novel solvent-free approach to construct uniform metal-organic framework (MOF) shell-derived carbon confined SnO₂ /Co (SnO₂ /Co@C) nanocubes via a two-step heat treatment is developed. In particular, MOF-coated CoSnO₃ hollow nanocubes are for the first time synthesized as the intermediate product by an extremely simple thermal solid-phase reaction, which is further developed as a general strategy to successfully obtain other uniform MOF-coated metal oxides. The as-synthesized SnO₂ /Co@C nanocubes, when tested as LIB anodes, exhibit a highly reversible discharge capacity of 800 mAh g^-1 after 100 cycles at 200 mA g^-1 and excellent cycling stability with a retained capacity of 400 mAh g^-1 after 1800 cycles at 5 A g^-1 . The experimental analyses demonstrate that these excellent performances are mainly ascribed to the delicate structure and a synergistic effect between Co and SnO₂ . This facile synthetic approach will greatly contribute to the development of functional metal oxide-based and MOF-assisted nanostructures in many frontier applications.

A Robust and Conductive Black Tin Oxide Nanostructure Makes Efficient Lithium-Ion Batteries Possible

SnO₂ -based lithium-ion batteries have low cost and high energy density, but their capacity fades rapidly during lithiation/delithiation due to phase aggregation and cracking. These problems can be mitigated by using highly conducting black SnO_2-x , which homogenizes the redox reactions and stabilizes fine, fracture-resistant Sn precipitates in the Li₂ O matrix. Such fine Sn precipitates and their ample contact with Li₂ O proliferate the reversible Sn → Li _x Sn → Sn → SnO₂ /SnO_2-x cycle during charging/discharging. SnO_2-x electrode has a reversible capacity of 1340 mAh g^-1 and retains 590 mAh g^-1 after 100 cycles. The addition of highly conductive, well-dispersed reduced graphene oxide further stabilizes and improves its performance, allowing 950 mAh g^-1 remaining after 100 cycles at 0.2 A g^-1 with 700 mAh g^-1 at 2.0 A g^-1 . Conductivity-directed microstructure development may offer a new approach to form advanced electrodes.

Mesoporous graphene/carbon framework embedded with SnO2 nanoparticles as a high-performance anode for lithium storage

A uniform graphene-based mesoporous carbon framework as a robust matrix for embedding SnO₂ nanoparticles for long-life lithium storage.

A facile post-process method to enhance crystallinity and electrochemical properties of SnO2/rGO composites with three-dimensional hierarchically porous structure

In this work, three SnO₂/reduced graphene oxide (SnO₂/rGO) composites with a three-dimensional hierarchically porous structure were synthesized via freeze drying and different annealing temperatures in an air atmosphere.

Tailored graphene based polyurethane composites for efficient electrostatic dissipation and electromagnetic interference shielding applications

Electrostatic dissipative and electromagnetic interference shielding materials were designed using thermally reduced graphene oxide nanosheets incorporated into a thermoplastic polyurethane matrix.