skip to main content

Explore Research Products in the NSF-PAR

Title: Design principles of pseudocapacitive carbon anode materials for ultrafast sodium and potassium-ion batteries
Sodium- and potassium-ion batteries are one of the most promising electrical energy storage devices at low cost, but their inferior rate and capacity have hampered broader applications such as electric vehicles and grids. Carbon nanomaterials have been demonstrated to have ultrafast surface-dominated ion uptake to drastically increase the rate and capacity, but trial-and-error approaches are usually used to find desired anode materials from numerous candidates. Here, we developed guiding principles to rationally screen pseudocapacitive anodes from numerous candidate carbon materials to create ultrafast Na- and K-ion batteries. The transition from pseudocapacitive to metal-battery mechanisms on heteroatom-doped graphene in charging process was revealed by the density functional theory methods. The results show that the graphene substrate can guide the preferential growth of K and Na along graphene plane, which inhibits dendrite development effectively in the batteries. An intrinsic descriptor is discovered to establish a volcano-shaped relationship that correlates the capacity with the intrinsic physical qualities of the doping structures, from which the best anode materials could be predicted. The predictions are in good agreement with the experimental results. The strategies for enhancing both the power and energy densities are proposed based on the predictions and experiments for the batteries.  more » « less
Award ID(s):
1662288
NSF-PAR ID:
10175587
Author(s) / Creator(s):
; ; ; ; ; ; ;
Date Published:
Journal Name:
Journal of Materials Chemistry A
Volume:
8
Issue:
16
ISSN:
2050-7488
Page Range / eLocation ID:
7756 to 7764
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; ( , Advanced Functional Materials)
    Abstract

    Ion‐insertion capacitors show promise to bridge the gap between supercapacitors of high power densities and batteries of high energy densities. While research efforts have primarily focused on Li+‐based capacitors (LICs), Na+‐based capacitors (SICs) are theoretically cheaper and more sustainable. Owing to the larger size of Na+compared to Li+, finding high‐rate anode materials for SICs has been challenging. Herein, an SIC anode architecture is reported consisting of TiO2nanoparticles anchored on a sheared‐carbon nanotubes backbone (TiO2/SCNT). The SCNT architecture provides advantages over other carbon architectures commonly used, such as reduced graphene oxide and CNT. In a half‐cell, the TiO2/SCNT electrode shows a capacity of 267 mAh g−1at a 1 C charge/discharge rate and a capacity of 136 mAh g−1at 10 C while maintaining 87% of initial capacity over 1000 cycles. When combined with activated carbon (AC) in a full cell, an energy density and power density of 54.9 Wh kg−1and 1410 W kg−1, respectively, are achieved while retaining a 90% capacity retention over 5000 cycles. The favorable rate capability, energy and power density, and durability of the electrode is attributed to the enhanced electronic and Na+conductivity of the TiO2/SCNT architecture.

     
    more » « less
  2. ; ; ; ; ; ; ; ; ; ; et al ( , Energy & Environmental Science)
    The development of anode materials with high-rate capability is critical to high-power lithium batteries. T-Nb 2 O 5 has been widely reported to exhibit pseudocapacitive behavior and fast lithium storage capability. However, the other polymorphs of Nb 2 O 5 prepared at higher temperatures have the potential to achieve even higher specific capacity and tap density than T-Nb 2 O 5 , offering higher volumetric power and energy density. Here, micrometer-sized H-Nb 2 O 5 with rich Wadsley planar defects (denoted as d-H-Nb 2 O 5 ) is designed for fast lithium storage. The performance of H-Nb 2 O 5 with local rearrangements of [NbO 6 ] octahedra blocks surpasses that of T-Nb 2 O 5 in terms of specific capacity, rate capability, and stability. A wide range variation in the valence of niobium ions upon lithiation was observed for defective H-Nb 2 O 5 via operando X-ray absorption spectroscopy. Operando extended X-ray absorption fine structure and ex situ Raman spectroscopy analyses reveal a large and reversible distortion of the structure in the two-phase region. Computation and ex situ X-ray diffraction analysis reveal that the shear structure expands along major lithium diffusion pathways and contracts in the direction perpendicular to the shear plane. Planar defects relieve strain through perpendicular arrangements of blocks, minimizing volume change and enhancing structural stability. In addition, strong Li adsorption on planar defects enlarges intercalation capacity. Different from nanostructure engineering, our strategy to modify the planar defects in the bulk phase can effectively improve the intrinsic properties. The findings in this work offer new insights into the design of fast Li-ion storage materials in micrometer sizes through defect engineering, and the strategy is applicable to the material discovery for other energy-related applications. 
    more » « less
  3. ; ; ; ; ; ; ; ; ; ( , Advanced Energy Materials)
    Abstract

    The growing demand for bioelectronics has generated widespread interest in implantable energy storage. These implantable bioelectronic devices, powered by a complementary battery/capacitor system, have faced difficulty in miniaturization without compromising their functionality. This paper reports on the development of a promising high‐rate cathode material for implantable power sources based on Li‐exchanged Na1.5VOPO4F0.5anchored on reduced graphene oxide (LNVOPF‐rGO). LNVOPF is unique in that it offers dual charge storage mechanisms, which enable it to exhibit mixed battery/capacitor electrochemical behavior. In this work, electrochemical Li‐ion exchange of the LNVOPF structure is characterized by operando X‐ray diffraction. Through designed nanostructuring, the charge storage kinetics of LNVOPF are improved, as reflected in the stored capacity of 107 mAh g−1at 20C. A practical full cell device composed of LNVOPF and T‐Nb2O5, which serves as a pseudocapacitive anode, is fabricated to demonstrate not only high energy/power density storage (100 Wh kg−1at 4000 W kg−1) but also reliable pulse capability and biocompatibility, a desirable combination for applications in biostimulating devices. This work underscores the potential of miniaturizing biomedical devices by replacing a conventional battery/capacitor couple with a single power source.

     
    more » « less
  4. ; ; ( , Advanced Energy Materials)
    Abstract

    Since their commercialization by Sony in 1991, graphite anodes in combination with various cathodes have enabled the widespread success of lithium‐ion batteries (LIBs), providing over 10 billion rechargeable batteries to the global population. Next‐generation nonaqueous alkali metal‐ion batteries, namely sodium‐ion batteries (SIBs) and potassium‐ion batteries (PIBs), are projected to utilize intercalation‐based carbon anodes as well, due to their favorable electrochemical properties. While traditionally graphite anodes have dominated the market share of LIBs, other carbon materials have been investigated, including graphene, carbon nanotubes, and disordered carbons. The relationship between carbon material properties, electrochemical performance, and charge storage mechanisms is clarified for these alkali metal‐ion batteries, elucidating possible strategies for obtaining enhanced cycling stability, specific capacity, rate capability, and safety aspects. As a key component in determining cell performance, the solid electrolyte interphase layer is described in detail, particularly for its dependence on the carbon anode. Finally, battery safety at extreme temperatures is discussed, where carbon anodes are susceptible to dendrite formation, accelerated aging, and eventual thermal runaway. As society pushes toward higher energy density LIBs, this review aims to provide guidance toward the development of sustainable next‐generation SIBs and PIBs.

     
    more » « less
  5. ; ; ; ; ; ; ( , Communications Chemistry)
    Abstract

    Rechargeable sodium-ion batteries are receiving intense interest as a promising alternative to lithium-ion batteries, however, the absence of high-performance anode materials limits their further commercialization. Here we prepare cobalt-doped tin disulfide/reduced graphene oxide nanocomposites via a microwave-assisted hydrothermal approach. These nanocomposites maintain a capacity of 636.2 mAh g−1after 120 cycles under a current density of 50 mA g−1, and display a capacity of 328.3 mA h g−1after 1500 cycles under a current density of 2 A g−1. The quantitative capacitive analysis demonstrates that the electrochemical performance of the nanocomposite originates from the combined effects of cobalt and sulfur doping, resulting in the enhanced pseudocapacitive contribution (52.8 to 89.8% at 1 mV s−1) of tin disulfide. This work provides insight into tuning the structure of layered transition metal dichalcogenides via heteroatom doping to develop high-performance anode materials for sodium-ion batteries.

     
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email