Peter Kopold

Uniform yolk–shell Sn4P3@C nanospheres as high-capacity and cycle-stable anode materials for sodium-ion batteries

Uniform yolk–shell Sn4P3@C nanospheres were facilely synthesized via a top-down phosphorized route with yolk–shell Sn@C nanospheres as the precursor. As anode materials for Na-ion batteries, they exhibit very high reversible capacity (790 mA h g−1), superior rate capability (reversible capabilities of 720, 651, 581, 505, and 421 mA h g−1 at 0.2C, 0.4C, 0.8C, 1.5C, and 3C, respectively) and stable cycling performance (a high capacity of 360 mA h g−1 at 1.5C after long 400 cycles).

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.

MOF-Derived Hollow Co9 S8 Nanoparticles Embedded in Graphitic Carbon Nanocages with Superior Li-Ion Storage.

Novel electrode materials consisting of hollow cobalt sulfide nanoparticles embedded in graphitic carbon nanocages (HCSP⊂GCC) are facilely synthesized by a top-down route applying room-temperature synthesized Co-based zeolitic imidazolate framework (ZIF-67) as the template. Owing to the good mechanical flexibility and pronounced structure stability of carbon nanocages-encapsulated Co9 S8 , the as-obtained HCSP⊂GCC exhibit superior Li-ion storage. Working in the voltage of 1.0-3.0 V, they display a very high energy density (707 Wh kg(-1) ), superior rate capability (reversible capabilities of 536, 489, 438, 393, 345, and 278 mA h g(-1) at 0.2, 0.5, 1, 2, 5, and 10C, respectively), and stable cycling performance (≈26% capacity loss after long 150 cycles at 1C with a capacity retention of 365 mA h g(-1) ). When the work voltage is extended into 0.01-3.0 V, a higher stable capacity of 1600 mA h g(-1) at a current density of 100 mA g(-1) is still achieved.

High Power-High Energy Sodium Battery Based on Threefold Interpenetrating Network.

A 3D tricontinuous Na3 V2 (PO4 )3 :reduced graphene oxide-carbon nanotube cathode is directly deposited on the current collector without any conductive additives or binders by a facile electrostatic spray deposition (ESD) technique. Such an electrode displays excellent rate capability and long cycling stability, which is rather typical of supercapacitors but is connected here with the much higher energy density of an efficient battery electrode.

Energy Storage Materials from Nature through Nanotechnology: A Sustainable Route from Reed Plants to a Silicon Anode for Lithium‐Ion Batteries

Silicon is an attractive anode material in energy storage devices, as it has a ten times higher theoretical capacity than its state-of-art carbonaceous counterpart. However, the common process to synthesize silicon nanostructured electrodes is complex, costly, and energy-intensive. Three-dimensional (3D) porous silicon-based anode materials have been fabricated from natural reed leaves by calcination and magnesiothermic reduction. This sustainable and highly abundant silica source allows for facile production of 3D porous silicon with very good electrochemical performance. The obtained silicon anode retains the 3D hierarchical architecture of the reed leaf. Impurity leaching and gas release during the fabrication process leads to an interconnected porosity and the reductive treatment to an inside carbon coating. Such anodes show a remarkable Li-ion storage performance: even after 4000 cycles and at a rate of 10 C, a specific capacity of 420 mA h g(-1) is achieved.

Peapod-Like Carbon-Encapsulated Cobalt Chalcogenide Nanowires as Cycle-Stable and High-Rate Materials for Sodium-Ion Anodes.

Peapod-like carbon-encapsulated cobalt chalcogenide nanowires are designed and synthesized by a facile method. The nanowires show excellent electrochemical performance for sodium storage, suggesting that chalcogenides, especially selenides, have potential as advanced anodes for sodium-ion batteries.

High Performance Graphene/Ni2P Hybrid Anodes for Lithium and Sodium Storage through 3D Yolk–Shell‐Like Nanostructural Design

A 3D yolk-shell-like electrode material composed of a porous interconnected graphene network and embedded Ni2 P nanoparticles is designed and fabricated by an assembly and self-template strategy. This novel nanoarchitecture integrates the advantages of nanostructure and microstructure, and provides highly efficient and stable electrochemical circuits involving the active nanoparticles, leading to excellent electrochemical performance in terms of reversibility, rate capability, and cycle stability.

A General Strategy to Fabricate Carbon-Coated 3D Porous Interconnected Metal Sulfides: Case Study of SnS/C Nanocomposite for High-Performance Lithium and Sodium Ion Batteries.

Transition metal sulfides have a great potential for energy storage due to the pronouncedly higher capacity (owing to conversion to metal or even alloy) than traditional insertion electrode materials. However, the poor cycling stability still limits the development and application in lithium and sodium ion batteries. Here, taking SnS as a model material, a novel general strategy is proposed to fabricate a 3D porous interconnected metal sulfide/carbon nanocomposite by the electrostatic spray deposition technique without adding any expensive carbonaceous materials such as graphene or carbon nanotube. In this way, small nanorods of SnS are generated with sizes of ≈10–20 nm embedded in amorphous carbon and self‐assembled into a 3D porous interconnected nanocomposite. The SnS:C is directly deposited on the Ti foil as a current collector and neither conductive additives nor binder are needed for battery assembly. Such electrodes exhibit a high reversible capacity, high rate capability, and long cycling stability for both lithium and sodium storage.

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.

Engineering nanostructured electrode materials for high performance sodium ion batteries: a case study of a 3D porous interconnected WS2/C nanocomposite

Much attention is being paid to sodium ion batteries (SIBs) in view of the abundance of sodium sources and the cost issues. Layered transition metal dichalcogenides (such as MoS2 and WS2) have great potential to be used as anode materials for sodium storage owing to their high capacity. However, they still suffer from low rate capability and poor cycling stability. Compared to MoS2, WS2 has been scarcely studied in view of sodium storage. Here, we report, for the first time, a 3D porous interconnected WS2/C nanocomposite prepared by an electrostatic spray deposition (ESD) technique, which is composed of nano-0D WS2, nano-1D CNTs and nano-2D reduced graphene oxide. Such a nanocomposite shows excellent rate performance and long cycling stability, demonstrating great potential for its use as a sodium anode. Moreover, this strategy can be applied to other electrode materials for both lithium and sodium batteries.