Yuan-Li Ding

Synthesizing Porous NaTi2(PO4)3 Nanoparticles Embedded in 3D Graphene Networks for High-Rate and Long Cycle-Life Sodium Electrodes

Sodium ion batteries attract increasing attention for large-scale energy storage as a promising alternative to the lithium counterparts in view of low cost and abundant sodium source. However, the large ion radius of Na brings about a series of challenging thermodynamic and kinetic difficulties to the electrodes for sodium-storage, including low reversible capacity and low ion transport, as well as large volume change. To mitigate or even overcome the kinetic problems, we develop a self-assembly route to a novel architecture consisting of nanosized porous NASICON-type NaTi2(PO4)3 particles embedded in microsized 3D graphene network. Such architecture synergistically combines the advantages of a 3D graphene network and of 0D porous nanoparticles. It greatly increases the electron/ion transport kinetics and assures the electrode structure integrity, leading to attractive electrochemical performance as reflected by a high rate-capability (112 mAh g(-1) at 1C, 105 mAh g(-1) at 5C, 96 mAh g(-1) at 10C, 67 mAh g(-1) at 50C), a long cycle-life (capacity retention of 80% after 1000 cycles at 10C), and a high initial Coulombic efficiency (>79%). This nanostructure design provides a promising pathway for developing high performance NASICON-type materials for sodium storage.

3D V6O13 Nanotextiles Assembled from Interconnected Nanogrooves as Cathode Materials for High-Energy Lithium Ion Batteries

Three-dimensional (3D) hierarchical nanostructures have been demonstrated as one of the most ideal electrode materials in energy storage systems owing to the synergistic combination of the advantages of both nanostructures and microstructures. In this work, 3D V6O13 nanotextiles built from interconnected 1D nanogrooves with diameter of 20-50 nm were fabricated via a facile solution-redox-based self-assembly route at room temperature, and the mesh size in the textile structure can be controllably tuned by adjusting the precursor concentration. It is suggested that the formation of 3D fabric structure built from nanogrooves is attributed to the rolling and self-assembly processes of produced V6O13 nanosheet intermediates. When evaluated as cathodes for lithium ion batteries (LIBs), the products delivered reversible capacities of 326 mAh g(-1) at 20 mA g(-1) and 134 mAh g(-1) at 500 mA g(-1), and a capacity retention of above 80% after 100 cycles at 500 mA g(-1). Importantly, the resulting textiles exhibit a specific energy as high as 780 Wh kg(-1), 44-56% higher than those of conventional cathodes, that is, LiMn2O4, LiCoO2, and LiFePO4. Furthermore, the 3D architectures retain good structural integrity upon cycling. Such findings reveal a great potential of V6O13 nanotextiles as high-energy cathode materials for LIBs.

A Lamellar Hybrid Assembled from Metal Disulfide Nanowall Arrays Anchored on a Carbon Layer: In Situ Hybridization and Improved Sodium Storage

A lamellar hybrid assembled from metal disulfide (MoS2 , WS2 ) nanowall arrays anchored on nitrogen-doped carbon layers is developed via an in situ hybridization strategy through a synergistic pyrolysis reaction of thiourea and oxometalates. Such a hybrid provides adequate electrical and chemical coupling between the active materials and the carbon substrate, thus realizing a high-efficiency electron-conduction/ion-transportation system and exhibiting excellent sodium-storage properties.

Graphene‐Protected 3D Sb‐based Anodes Fabricated via Electrostatic Assembly and Confinement Replacement for Enhanced Lithium and Sodium Storage

Alloy anodes have shown great potential for next-generation lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). However, these applications are still limited by inherent huge volume changes and sluggish kinetics. To overcome such limitations, graphene-protected 3D Sb-based anodes grown on conductive substrate are designed and fabricated by a facile electrostatic-assembling and subsequent confinement replacement strategy. As binder-free anodes for LIBs, the obtained electrode exhibits reversible capacities of 442 mAh g(-1) at 100 mA g(-1) and 295 mAh g(-1) at 1000 mA g(-1), and a capacity retention of above 90% (based on the 10th cycle) after 200 cycles at 500 mA g(-1). As for sodium storage properties, the reversible capacities of 517 mAh g(-1) at 50 mA g(-1) and 315 mAh g(-1) at 1000 mA g(-1), the capacity retention of 305 mAh g(-1) after 100 cycles at 300 mA g(-1) are obtained, respectively. Furthermore, the 3D architecture retains good structural integrity after cycling, confirming that the introduction of high-stretchy and robust graphene layers can effectively buffer alloying anodes, and simultaneously provide sustainable contact and protection of the active materials. Such findings show its great potential as superior binder-free anodes for LIBs and SIBs.

Rapid and Up-Scalable Fabrication of Free-Standing Metal Oxide Nanosheets for High-Performance Lithium Storage

Free-standing α-Fe2 O3 nanosheets, SnO2 mesoporous nanosheets and sandwich-like polyaniline (PAN)/SnO2 /PAN nanosheets are fabricated at very mild conditions (room temperature or 60 °C) via a galvanic replacement method for the first time. These nanosheets show excellent high-rate capability and long-term durability as anodes for lithium-ion batteries.

Large-scale low temperature fabrication of SnO2 hollow/nanoporous nanostructures: the template-engaged replacement reaction mechanism and high-rate lithium storage

The morphology-controlled synthesis of SnO2 hollow/nanoporous nanostructures (nanotubes, urchin-like morphologies and nanospheres) was achieved via a template-engaged replacement reaction at a mild temperature (lower than 80 °C). The formation mechanism of hollow interior and nanoporous walls for the obtained SnO2 nanostructures (SnO2 nanotubes were used as an example) was investigated based on TEM and HRTEM observations during different reaction stages. It is found that bridge voids firstly form at the MnO2/SnO2 interface, followed by the inward development of voids before the MnO2 core is completely consumed. Two types of short-circuited galvanic cells, MnO2/Mn(2+)∣SnO2/Sn(2+) and concentration cell-SnO2/Sn(2+) (interior)∣SnO2/Sn(2+) (exterior), are probably responsible for the formation of SnO2 nanotubes and outward growth of SnO2 along MnO2. Moreover, the calculation result of the outer diameter of SnO2 nanotubes is in good agreement with the observation results by SEM and TEM. When evaluated as anodes for lithium ion batteries (LIBs), the three SnO2 nanostructures exhibit superior rate capability and cycling performance. Especially, SnO2 nanotubes present the best rate capability: specific capacities of above 800 mA h g(-1) at 200 mA g(-1) and about 500 mA h g(-1) at 4000 mA g(-1) were achieved, respectively. Importantly, the 1D morphology of SnO2 nanotubes can be well preserved after prolonged cycling at a relatively high current density, indicating good structural stability of the resulting nanotubes during the Li(+) insertion/extraction process. These results indicate that the obtained SnO2 hollow/nanoporous nanostructures would be promising anode materials for next-generation LIBs.

Nanosheets of Earth-Abundant Jarosite as Novel Anodes for High-Rate and Long-Life Lithium-Ion Batteries

Nanosheets of earth-abundant jarosite were fabricated via a facile template-engaged redox coprecipitation strategy at room temperature and employed as novel anode materials for lithium-ion batteries (LIBs) for the first time. These 2D materials exhibit high capacities, excellent rate capability, and prolonged cycling performance. As for KFe3(SO4)2(OH)6 jarosite nanosheets (KNSs), the reversible capacities of above 1300 mAh g(-1) at 100 mA g(-1) and 620 mAh g(-1) after 4000 cycles at a very high current density of 10 A g(-1) were achieved, respectively. Moreover, the resulting 2D nanomaterials retain good structural integrity upon cycling. These results reveal great potential of jarosite nanosheets as low-cost and high-performance anode materials for next-generation LIBs.

Anodes: Graphene-Protected 3D Sb-based Anodes Fabricated via Electrostatic Assembly and Confinement Replacement for Enhanced Lithium and Sodium Storage (Small 45/2015)

Graphene-protected 3D Sb-based anodes are designed and fabricated by Y. Yu and co-workers using a facile electrostatic assembly and confinement replacement method. On page 6026, in this fabrication, commercial nickel foam is used as both a 3D growth substrate and as a reductant for converting Sb(3+) to Sb. When evaluated as binder-free anodes for Li-ion and sodium-ion batteries, the obtained 3D electrodes exhibit remarkably enhanced lithium and sodium storage performance.