Superior Sodium Storage Performance Research Articles

Graphene-Based Phosphorus-Doped Carbon as Anode Material for High-Performance Sodium-Ion Batteries

Graphene-based phosphorus-doped carbon (GPC) is prepared through a facile and scalable thermal annealing method by triphenylphosphine and graphite oxide as precursor. The P atoms are successfully doped into few layer graphene with two forms of P–O and P–C bands. The GPC used as anode material for Na-ion batteries delivers a high charge capacity 284.8 mAh g−1 at a current density of 50 mA g−1 after 60 cycles. Superior cycling performance is also shown at high charge−discharge rate: a stable charge capacity 145.6 mAh g−1 can be achieved at the current density of 500 mA g−1 after 600 cycles. The result demonstrates that the GPC electrode exhibits good electrochemical performance (higher reversible charge capacity, super rate capability, and long-term cycling stability). The excellent electrochemical performance originated from the large interlayer distance, large amount of defects, vacancies, and active site caused by P atoms doping. The relationship of P atoms doping amount with the Na storage properties is also discussed. This superior sodium storage performance of GPC makes it as a promising alternative anode material for sodium-ion batteries.

Confined Amorphous Red Phosphorus in MOF-Derived N-Doped Microporous Carbon as a Superior Anode for Sodium-Ion Battery.

Red phosphorus (P) has attracted intense attention as promising anode material for high-energy density sodium-ion batteries (NIBs), owing to its high sodium storage theoretical capacity (2595 mAh g-1 ). Nevertheless, natural insulating property and large volume variation of red P during cycling result in extremely low electrochemical activity, leading to poor electrochemical performance. Herein, the authors demonstrate a rational strategy to improve sodium storage performance of red P by confining nanosized amorphous red P into zeolitic imidazolate framework-8 (ZIF-8) -derived nitrogen-doped microporous carbon matrix (denoted as P@N-MPC). When used as anode for NIBs, the P@N-MPC composite displays a high reversible specific capacity of ≈600 mAh g-1 at 0.15 A g-1 and improved rate capacity (≈450 mAh g-1 at 1 A g-1 after 1000 cycles with an extremely low capacity fading rate of 0.02% per cycle). The superior sodium storage performance of the P@N-MPC is mainly attributed to the novel structure. The N-doped porous carbon with sub-1 nm micropore facilitates the rapid diffusion of organic electrolyte ions and improves the conductivity of the encapsulated red P. Furthermore, the porous carbon matrix can buffer the volume change of red P during repeat sodiation/desodiation process, keeping the structure intact after long cycle life.

Superior sodium storage performance of additive-free V2O5 thin film electrodes

A V2O5 thin film electrode with superior sodium storage performance was fabricated by a facile and cost-efficient cathodic deposition method.

Facile in situ synthesis of crystalline VOOH-coated VS2microflowers with superior sodium storage performance

Crystalline VOOH-coated VS2microflowers constructed from nanosheets arein situprepared by a facile one-step hydrothermal method.

Fabrication of an MOF-derived heteroatom-doped Co/CoO/carbon hybrid with superior sodium storage performance for sodium-ion batteries

MOF-derived heteroatom (Ni and N)-doped Co/CoO/carbon hybrid with superior sodium storage performance for sodium-ion batteries have been fabricated from bimetallic Ni–Co-ZIF particles through annealing under argon atmosphere at 500 °C.

Na3V2(PO4)3 coated by N-doped carbon from ionic liquid as cathode materials for high rate and long-life Na-ion batteries.

A facile and simple hydrothermal assisted sol-gel route was developed to prepare nitrogen doped carbon coated Na3V2(PO4)3 nanocomposites (denoted as NVP@C-N) as cathodes for sodium ion batteries (NIBs). An ionic liquid (EMIm-dca) was used as the nitrogen doped carbon source. The optimized N-doped carbon coated Na3V2(PO4)3 (denoted as NVP@C-N150) displays a very thin and uniform N-doped carbon coating layer (thickness: ∼2 nm), showing an excellent sodium storage performance (85 mA h g-1 at 20 C after 5000 cycles) and high rate capability (71 mA h g-1 at 80 C). Such a superior sodium storage performance derives from the nitrogen doping carbon coating, triggering amounts of extrinsical defects and active sites in the N-doped amorphous carbon layer, which highly accelerates Na-ion and electron transport. This approach is simple, facile and shows easy scale-up. It could be extended to other materials for energy storage.

Hierarchically porous CoNiO2nanosheet array films with superior sodium storage performance

The hierarchically porous CoNiO2nanosheet array film preparedviaa low-temperature solvothermal method manifests superior sodium storage performance.

Carbon intercalated porous NaTi2(PO4)3spheres as high-rate and ultralong-life anodes for rechargeable sodium-ion batteries

Carbon intercalated porous NaTi2(PO4)3spheres have been synthesized by a facile route. When evaluated as anodes for SIBs, these spheres delivered superior sodium storage performance in terms of high reversible capacity, stable cycling and good rate performances.

Electrospinning Synthesis of Mesoporous MnCoNiOx@Double-Carbon Nanofibers for Sodium-Ion Battery Anodes with Pseudocapacitive Behavior and Long Cycle Life.

In this work, MnCoNiOx (denoted as MCNO) nanocrystals (with a size of less than 30 nm) finely encapsulated in double-carbon (DC, including reduced graphene oxide and amorphous carbon derived by polymer) composite nanofibers (MCNO@DC) were successfully synthesized via an electrospinning method followed by a sintering treatment. The as-obtained MCNO@DC nanofibers present superior sodium storage performance and retain an especially high specific capacity of 230 mAh g-1 with a large capacity retention of about 96% at 0.1 A g-1 after 500 cycles and a specific capacity of 107 mAh g-1 with capacity retention of about 89% at 1 A g-1 after 6500 cycles. The outstanding cycle characteristic is mainly due to the tiny MCNO nanoparticles, which shorten the ion migration distance, and the three-dimensional DC framework, which remarkably promotes the electronic transfer and efficiently limits the volume expansion during the progress of insertion and extraction of Na+ ions. Moreover, nitrogen doped in carbon is able to improve the electrochemical capability as well. Finally, kinetic analysis of the redox reactions is used to verify the pseudocapacitive mechanism in charge storage and the feasibility of using MCNO@DC composite nanofibers as an anode for sodium-ion batteries with the above-mentioned behavior.

SnO2 particles anchored on N-doped graphene surface as sodium-ion battery anode with enhanced electrochemical capability

The small-size SnO2 particles uniformly dispersed on the nitrogen doping graphene nanocomposites (SnO2-N-GNS) have been successfully synthesized by a mild hydrothermal method with the precursors of graphene oxide, urea and SnCl4.5H2O. The phase (XRD, EDX and XPS) and morphology (SEM, TEM) analysis further confirm the obtained products. When the composite served as anode material in sodium ion batteries (SIBs), it delivers superior sodium storage performance with reversible discharge capacity of 294.4mAhg−1 at a current density of 50mAg−1 in the voltage range from 0.01–3V after 50 discharge/charge cycles, which is much higher than that of SnO2-GNS (182.9mAhg−1) and N-GNS (114.9mAhg−1). Besides, the SnO2-N-GNS electrode also exhibits admirable rate stability with the discharge capacity of 206mAhg−1 even at 800mAg−1. More importantly, the SnO2-N-GNS shows lower internal resistance and larger sodium-ion diffusion coefficient. These enhanced electrochemical performances of SnO2-N-GNS are due to the N-doping defects and the homogeneous dispersion of SnO2 particles.

Carbon-coated hierarchical NaTi2(PO4)3 mesoporous microflowers with superior sodium storage performance

NASICON structured NaTi2(PO4)3 with stable and open framework has become a promising electrode material for sodium-ion batteries. However, the intrinsic low electronic conductivity of NaTi2(PO4)3 leads to inferior rate capability and poor active material utilization. Herein, we first report the synthesis of carbon-coated hierarchical NaTi2(PO4)3 mesoporous microflowers (NTP/C-F), via a facile and controllable solvothermal method and subsequent annealing treatment. The unique structural features endow the NTP/C-F with excellent structural stability, enhanced charge transfer kinetics, and suppressed polarization. This architecture exhibits superior sodium storage performance: high initial capacity (125mAhg−1 at 1C), outstanding rate capability (95mAhg−1 at 100C), and ultra-long cycling stability (capacity retention of 77.3% after 10,000 cycles at 20C). Time-resolved in-situ X-ray diffraction study reveals a typical two-phase electrochemical reaction with reversible structure change. This work suggests the integration of hierarchical structure and carbon coating provides a promising approach for boosting the electrochemical performances of battery electrode materials.

Hierarchical tubular structures constructed from rutile TiO2 nanorods with superior sodium storage properties

Hierarchical tubular structures constructed from rutile TiO2 nanorods are fabricated, using MnO2 nanorods as sacrificial templates. The resultant rutile TiO2 hierarchical nanotubes show unique structural features (hierarchical, hollow) and a large surface area (180m2g−1), which substantially improve their electrochemical performance. This type of hierarchical structures with high porosity produced by neighboring building blocks, are desirable for the development of sodium ion batteries, because the large amounts of pores can enhance the contact areas between electrode and electrolyte, and faciliate the ion diffusion during the charge/discharge process. As an anode material for sodium ion batteries, these hierarchical nanotubes deliver a high reversible capacity of 221mAhg−1 at 0.3C (100mAg−1), superior rate capability with a stable capacity of 71mAhg−1 at 15C, and good long-term cycling stability with a capacity of 79mAhg−1 after 1000 cycles at 3C. The superior sodium storage performances make this rutile TiO2 hierarchical nanotube a promising anode metarial for sodium ion batteries.

Nanostructured Black Phosphorus/Ketjenblack-Multiwalled Carbon Nanotubes Composite as High Performance Anode Material for Sodium-Ion Batteries.

Sodium-ion batteries are promising alternatives to lithium-ion batteries for large-scale applications. However, the low capacity and poor rate capability of existing anodes for sodium-ion batteries are bottlenecks for future developments. Here, we report a high performance nanostructured anode material for sodium-ion batteries that is fabricated by high energy ball milling to form black phosphorus/Ketjenblack-multiwalled carbon nanotubes (BPC) composite. With this strategy, the BPC composite with a high phosphorus content (70 wt %) could deliver a very high initial Coulombic efficiency (>90%) and high specific capacity with excellent cyclability at high rate of charge/discharge (∼1700 mAh g(-1) after 100 cycles at 1.3 A g(-1) based on the mass of P). In situ electrochemical impedance spectroscopy, synchrotron high energy X-ray diffraction, ex situ small/wide-angle X-ray scattering, high resolution transmission electronic microscopy, and nuclear magnetic resonance were further used to unravel its superior sodium storage performance. The scientific findings gained in this work are expected to serve as a guide for future design on high performance anode material for sodium-ion batteries.

Preparation of nitrogen- and phosphorous co-doped carbon microspheres and their superior performance as anode in sodium-ion batteries

Sodium-ion batteries are considered a top alternative to lithium-ion batteries for large-scale renewable energy storage units due to their low cost and the abundance of sodium-bearing precursors in the earth's mineral deposits. However, the absence of a suitable negative electrode material hinders their development. In this contribution, we report the preparation of nitrogen and phosphorous co-doped carbon microspheres through a hydrothermal process followed by heat treatment in presence of (NH4)2HPO4 and investigate their electrochemical performance as anode in sodium-ion batteries. Benefiting from the N, P co-doping, the obtained N, P co-doped carbon microspheres demonstrates high specific capacity, excellent cycle stability as well as good rate performance. The as prepared N, P co-doped carbon microspheres can deliver a reversible capacity of 305 mAh g−1 at a current density of 0.1 A g−1 and even deliver a capacity of 136 mAh g−1 at 5 A g−1. This superior sodium storage performance of N, P co-doped carbon makes it as a promising low-cost anode candidate for sodium-ion batteries.