Capacity For Sodium-ion Batteries Research Articles

Pre-crosslinking enables a promising cyclodextrin-derived carbon anode with large plateau capacity for sodium ion batteries

The cross-linking reaction tends to produce more sp3-hybrid carbon, which finally results in more curved and shorter carbon layers as well as much more closed pores. Therefore, we can regulate the closed pores and platform capacity.

P-doped spherical hard carbon with high initial coulombic efficiency and enhanced capacity for sodium ion batteries

We propose a repair strategy based on doping a trace amount of P to achieve a high capacity along with a high ICE, the obtained PHC-0.2 possesses a large interlayer space that facilitates Na+ storage and transportation.

Ester-based anti-freezing electrolyte achieving ultra-low temperature cycling for sodium-ion batteries

With the continuous advancement of industrialization, sodium-ion batteries (SIBs) need to operate in various challenging circumstances, particularly in extremely cold conditions. However, at ultra-low temperatures, the reduced ionic conductivity and sluggish Na+ migration of commonly carbonate-based electrolytes will inevitably lead to a sharp decrease in the capacity of SIBs. Herein, we design a carboxylate ester-based electrolyte with excellent ultra-low temperature performance by straightforward cosolvent strategy. Due to the low viscosity, melting point, and sufficient ionic conductivity of the designed electrolyte, the resulting Na||Na3V2(PO4)2O2F can achieve the capacity retention of 96% (100 cycles at 0.1 C) at –40 °C and can also operate stably even at –50 °C. Besides, galvanostatic intermittent titration technique (GITT), ex-situ X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (TEM) tests are employed to analyze and confirm that the carboxylate ester-based electrolyte promotes robust and uniform cathode/electrolyte interface layer formation and accelerates ion diffusion kinetics, which collectively facilitates the better low-temperature performance. In addition, the assembled hard carbon||NVPOF full cells further prove the practicability of the carboxylate ester-based electrolyte at low-temperature, which delivers high discharge capacity of 108.4 and 73.0 mAh g–1 at –25 and –40 °C. This work affords a new avenue for designing advanced low-temperature electrolytes for SIBs.

A Stress Self-Adaptive Structure to Suppress the Chemo-mechanical Degradation for High Rate and Ultralong Cycle Life Sodium Ion Batteries.

Transition-metal phosphides (TMPs) as typical conversion-type anode materials demonstrate extraordinary theoretical charge storage capacity for sodium ion batteries, but the unavoidable volume expansion and irreversible capacity loss upon cycling represent their long-standing limitations. Herein we report a stress self-adaptive structure with ultrafine FeP nanodots embedded in dense carbon microplates skeleton (FeP@CMS) via the spatial confinement of carbon quantum dots (CQDs). Such an architecture delivers a record high specific capacity (778 mAh g-1 at 0.05 A g-1) and ultra-long cycle stability (87.6% capacity retention after 10,000 cycles at 20 A g-1), which outperforms the state-of-the-art literature. We decode the fundamental reasons for this unprecedented performance, that such an architecture allows the spontaneous stress transfer from FeP nanodots to the surrounding carbon matrix, thus overcomes the intrinsic chemo-mechanical degradation of metal phosphides.

A Stress Self‐Adaptive Structure to Suppress the Chemo‐mechanical Degradation for High Rate and Ultralong Cycle Life Sodium Ion Batteries

AbstractTransition‐metal phosphides (TMPs) as typical conversion‐type anode materials demonstrate extraordinary theoretical charge storage capacity for sodium ion batteries, but the unavoidable volume expansion and irreversible capacity loss upon cycling represent their long‐standing limitations. Herein we report a stress self‐adaptive structure with ultrafine FeP nanodots embedded in dense carbon microplates skeleton (FeP@CMS) via the spatial confinement of carbon quantum dots (CQDs). Such an architecture delivers a record high specific capacity (778 mAh g−1 at 0.05 A g−1) and ultra‐long cycle stability (87.6 % capacity retention after 10 000 cycles at 20 A g−1), which outperform the state‐of‐the‐art literature. We decode the fundamental reasons for this unprecedented performance, that such an architecture allows the spontaneous stress transfer from FeP nanodots to the surrounding carbon matrix, thus overcomes the intrinsic chemo‐mechanical degradation of metal phosphides.

Cr/S co-doped carbon nanofibers via electrospinning for high-performance Li/Na ion batteries

Carbon nanofibers (CNFs) have high specific surface area and great electrochemical stability as the anode materials for alkali metal batteries. However, they also have many defects such as low specific capacity and excessive voltage hysteresis, which hinder their wide application. In this work, Cr/S co-doped CNFs (Cr/S@CNFs) are successfully synthesized via electrospinning technique combined with high temperature treatment. As the anode for lithium ion batteries (LIBs), the Cr/S@CNFs electrode exhibits excellent cycle stability (291.7 mAh g−1 at 2 A g−1 after 900 cycles) and high rate performance (221.3 mAh g−1 at 10 A g−1). Moreover, the electrode also obtains the discharge capacity of 266.2 mAh g−1 after 100 cycles at 0.1 A g−1, showing good ion storage capacity for sodium ion batteries (SIBs). Such outstanding electrochemical performances attribute to the co-doping of Cr and S elements, presenting a reliable and efficient approach for the synthesis of high-performance anode materials.

Multilayer SnS-SnS2@GO heterostructures nanosheet as anode material for Sodium ion battery with high capacity and stability

SnS and SnS2 are two promising anode materials with excellent theoretical capacity for Sodium ion batteries. However, severe volume collapse and low electric charge conductivity dramatically affect the electrochemical performance of SnS and SnS2. As a consequence, SnS-SnS2 heterostructures are constructed to improve the conductivity of the anode material. The volume effect is prevented by compounding with Graphene Oxide (GO) to ensure cyclic stability and improve the initial coulombic efficiency of anode materials. The first-principles simulation is used to simulate SnS, SnS2, SnS-SnS2 and SnS-SnS2 @GO respectively, and the comparison is made through actual experiments. Experimental studies indicate that SnS-SnS2 @GO processes superior conductivity and cycle stability, unique nano-flake structure and the composite modification of GO can restrain the volume effect and ensure long cycle stability of the anode material (450.6 mAh·g−1 after 100 cycles). Moreover, attributing to the p-n heterostructures, the internal charges transfer and improve the electrical conductivity of SnS-SnS2 can be promoted obviously. Simultaneously, it has been detected that the multilayer SnS-SnS2 heterostructures combining GO effectively improve the conductivity and ensure good structure stability. Therefore, SnS-SnS2 @GO composites can be considered as an ideal anode material for sodium ion batteries.

Revealing the Various Electrochemical Behaviors of Sn4P3 Binary Alloy Anodes in Alkali Metal Ion Batteries

AbstractSn4P3 binary alloy anode has attracted much attention, not only because of the synergistic effect of P and Sn, but also its universal popularity in alkali metal ion batteries (AIBs), including lithium‐ion batteries (LIBs), sodium‐ion batteries (SIBs), and potassium‐ion batteries (PIBs). However, the alkali metal ion (A+) storage and capacity attenuation mechanism of Sn4P3 anodes in AIBs are not well understood. Herein, a combination of ex situ X‐ray diffraction, transmission electron microscopy, and density functional theory calculations reveals that the Sn4P3 anode undergoes segregation of Sn and P, followed by the intercalation of A+ in P and then in Sn. In addition, differential electrochemical curves and ex situ XPS results demonstrate that the deep insertion of A+ in P and Sn, especially in P, contributes to the reduction in capacity of AIBs. Serious sodium metal dendrite growth causes further reduction in the capacity of SIBs, while in PIBs it is the unstable solid electrolyte interphase and sluggish dynamics that lead to capacity decay. Not only the failure mechanism, including structural deterioration, unstable SEI, dendrite growth, and sluggish kinetics, but also the modification strategy and systematic analysis method provide theoretical guidance for the development of other alloy‐based anode materials.

Hierarchical polyaromatic hydrocarbons (PAH) with superior sodium storage properties

Designing a structurally stable anode with a high reversible capacity for sodium ion batteries (SIBs) is particularly crucial so that batteries are able to meet the requirements for large-scale applications in grid electrical energy storage.

Co2B2O5 as an anode material with high capacity for sodium ion batteries

In this work, a flake-structured Co2B2O5 material was obtained by a simple sol–gel method and researched for use in sodium ion batteries firstly. When serving as anode material for sodium ion batteries, it exhibits the high initial reversible capacity of 466 mAh·g−1 at a current density of 100 mA·g−1. Through the recombination of carbon nanotubes (CNTs), the composite Co2B2O5/CNTs delivers the initial reversible capacity of 464 mAh·g−1, and 324 mAh·g−1 is obtained after 60 cycles under the current density of 100 mA·g−1. When under the current density of 1000 mA·g−1, a capacity of 236 mAh·g−1 is obtained for Co2B2O5/CNTs while 160 mAh·g−1 for Co2B2O5. Moreover, the sodium storage behavior of Co2B2O5 is identified by kinetic analysis. The higher Na+ capacitive contribution of Co2B2O5/CNTs could account for the enhanced rate performance. The results indicate that Co2B2O5 is a promising anode material for sodium ion batteries.

Rational Design of Layered SnS2 on Ultralight Graphene Fiber Fabrics as Binder-Free Anodes for Enhanced Practical Capacity of Sodium-Ion Batteries

HighlightsLayered SnS2 nanosheets/reduced graphene fiber (SnS2@rGF) hybrid fabrics were fabricated as binder-free electrodes.Ultralight rGF fabrics could increase the active materials loading to a high level of 67.2 wt% in the whole electrode, which is much higher than that of traditional slurry coating electrodes by using Cu or Al foil as current collectors.The practical capacity based on the weight of electrode could increase to as high as ~ 538 mAh g−1 exceeding to the slurry coating electrodes.

Vertically constructed monolithic electrodes for sodium ion batteries: toward low tortuosity and high energy density

A vertically aligned architecture for an electrode is constructed through physical vapor deposition which benefits the charge transport kinetics and leads to an ultrahigh volumetric capacity for sodium ion batteries.

Three-Dimensional SnS Decorated Carbon Nano-Networks as Anode Materials for Lithium and Sodium Ion Batteries.

The three-dimensional (3D) SnS decorated carbon nano-networks (SnS@C) were synthesized via a facile two-step method of freeze-drying combined with post-heat treatment. The lithium and sodium storage performances of above composites acting as anode materials were investigated. As anode materials for lithium ion batteries, a high reversible capacity of 780 mAh·g−1 for SnS@C composites can be obtained at 100 mA·g−1 after 100 cycles. Even cycled at a high current density of 2 A·g−1, the reversible capacity of this composite can be maintained at 610 mAh·g−1 after 1000 cycles. The initial charge capacity for sodium ion batteries can reach 333 mAh·g−1, and it retains a reversible capacity of 186 mAh·g−1 at 100 mA·g−1 after 100 cycles. The good lithium or sodium storage performances are likely attributed to the synergistic effects of the conductive carbon nano-networks and small SnS nanoparticles.

Lanthanide doping induced electrochemical enhancement of Na2Ti3O7 anodes for sodium-ion batteries.

Na2Ti3O7 is considered as a promising anode material for sodium ion batteries (SIBs) due to its excellent high-rate performance compared with hard carbons. However, the electrochemical performance of Na2Ti3O7 is heavily limited by its low electrical conductivity. In this study, we synthesized a series of lanthanide (Ln = La, Ce, Nd, Sm, Gd, Er, and Yb) doped microsized Na2Ti3O7 anode materials and systematically studied the electrochemical performance. Compared with pristine Na2Ti3O7, all the doped samples show superior electrochemical performance. Especially, the Yb3+ doped sample not only delivers a high reversible capacity of 89.4 mA h g-1 at 30C, but also maintains 71.6 mA h g-1 at 5C after 1600 cycles, nearly twice that of pristine Na2Ti3O7. It is found for the first time that the enhancement in doped samples is attributed to the introduction of lanthanides which induces lattice distortion and oxygen vacancies.