Heteroatom Doping: An Effective Way to Boost Sodium Ion Storage

Abstract

In response to the change of energy landscape, sodium‐ion batteries (SIBs) are becoming one of the most promising power sources for the post‐lithium‐ion battery (LIB) era due to the cheap and abundant nature of sodium, and similar electrochemical properties to LIBs. The electrochemical performance of electrode materials for SIBs is closely bound up with their crystal structures and intrinsic electronic/ionic states. Apart from nanoscale design and conductive composite strategies, heteroatom doping is another effective way to enhance the intrinsic transfer characteristics of sodium ions and electrons in crystal structures to accelerate reaction kinetics and thereby achieve high performance. In this review, the recent advancements in heteroatom doping for sodium ion storage of electrode materials are reviewed. Specifically, different doping strategies including nonmetal element doping (e.g., nitrogen, sulfur, phosphorous, boron, fluorine), metal element doping (magnesium, titanium, iron, aluminum, nickel, copper, etc.), and dual/triple doping (such as N–S, N–P, N–S–P) are reviewed and summarized in detail. Furthermore, various doping methods are introduced and their advantages and disadvantages are discussed. The doping effect on crystal structure and intrinsic electronic/ionic state are illustrated and the relationship with capacity and energy/power density is interrogated. Finally, future development trends in doping strategies for advanced SIBs electrodes are analyzed.

Defects in Hard Carbon: Where Are They Located and How Does the Location Affect Alkaline Metal Storage?

“…From experimental evidence, it has also been observed that extrinsic oxygen defects can arise as a consequence of nitrogen doping. [ 68 ] In this section, we investigate two nitrogen‐ and oxygen‐containing defects, the N C O C and N C 2O C defects ( Figure ). These defects are geometrically similar to the 2O C and 3O C defects, respectively.…”

Coupling PEDOT on Mesoporous Vanadium Nitride Arrays for Advanced Flexible All‐Solid‐State Supercapacitors

“…[18][19][20][21] However, metal oxides and metal sulfides show poor intrinsic electronic conductivity, and thereby lead to compromised power/energy performance. [22,23] Meanwhile, metal nitride, typically vanadium nitride (VN), has been demonstrated to realize both high energy/power density in view of its high electrical conductivity (1.67 × 10 6 S m −1 ), wide potential window (1.0-1.2 V), and superior electrochemical redox reactivity. [24] With the help of nanoscale design, various VN nanostructures (such as nanosheets, nanorods, nanowires, nanoflowers) have been explored and boosted electrochemical kinetics and utilization are verified in these systems due to larger surface area and increased active sites.…”

Carbon‐Based Capacitive Deionization Electrodes: Development Techniques and its Influence on Electrode Properties

“…Heteroatom doping is a widely used technique in altering the chemical and physical properties of carbon such as porosity, conductivity, wettability and capacitance [111–112] . It involves the substitution of carbon with a heteroatom (N, P, S, B, etc.)…”

“…These examples show that heteroatom doping can produce multiple effects even with single and/or multiple dopants. Nitrogen doping seems to be the popular dopant of choice not just with CDI but also with energy storage devices [112] . However, it is evident that more can be explored in this area such as using other dopants like fluorine, or other dopant combinations to create synergistic effects on the properties of carbon.…”