Hard carbons for sodium-ion batteries: Structure, analysis, sustainability, and electrochemistry

Dou, Xiaoming; Hasa, Ivana; Saurel, Damien; Vaalma, Christoph; Wu, Li‐Ming; Buchholz, Daniel; Bresser, Dominic; Komaba, Shinichi; Passerini, Stefano

doi:10.1016/j.mattod.2018.12.040

“…The (002) hump peaks of ENDCs reveal the amorphous nature of ENDCs without well‐defined (002) interlayer spacing. Since XRD patterns cannot clarify the arrangements and lengths of turbostratic GNDs in amorphous carbons, R value, introduced by Dahn et al., was applied to evaluate the order degree of amorphous carbons . With the increase of pyrolysis temperature, ENDCs show increased R values from 1.66 of ENDC500 to 1.85 of ENDC700 and finally to 1.91 of NDC900, which indicates the increased order degree and is in good agreement with the TEM results.…”

Section: Resultssupporting

confidence: 55%

A Site‐Selective Doping Strategy of Carbon Anodes with Remarkable K‐Ion Storage Capacity

Zhang

¹

,

Cao

²

,

Wang

³

et al. 2020

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The limited potassium‐ion intercalation capacity of graphite hampers development of potassium‐ion batteries (PIB). Edge‐nitrogen doping is an effective approach to enhance K‐ion storage in carbonaceous materials. One shortcoming is the lack of precise control over producing the edge‐nitrogen configuration. Here, a molecular‐scale copolymer pyrolysis strategy is used to precisely control edge‐nitrogen doping in carbonaceous materials. This process results in defect‐rich, edge‐nitrogen doped carbons (ENDC) with a high nitrogen‐doping level (up to 10.5 at %) and a high edge‐nitrogen ratio (87.6 %). The optimized ENDC exhibits a high reversible capacity of 423 mAh g−1, a high initial Coulombic efficiency of 65 %, superior rate capability, and long cycle life (93.8 % retention after three months). This strategy can be extended to design other edge‐heteroatom‐rich carbons through pyrolysis of copolymers for efficient storage of various mobile ions.

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“…The (002) hump peaks of ENDCs reveal the amorphous nature of ENDCs without well-defined (002) interlayer spacing. Since XRD patterns cannot clarify the arrangements and lengths of turbostratic GNDs in amorphous carbons, [38] R value, introduced by Dahn et al, was applied to evaluate the order degree of amorphous carbons. [39] With the increase of pyrolysis temperature, ENDCs show increased R values from 1.66 of ENDC500 to 1.85 of ENDC700 and finally to 1.91 of NDC900, which indicates the increased order degree and is in good agreement with the TEM results.…”

Section: Resultsmentioning

confidence: 99%

A Site‐Selective Doping Strategy of Carbon Anodes with Remarkable K‐Ion Storage Capacity

Zhang

¹

,

Cao

²

,

Wang

³

et al. 2020

View full text Add to dashboard Cite

The limited potassium‐ion intercalation capacity of graphite hampers development of potassium‐ion batteries (PIB). Edge‐nitrogen doping is an effective approach to enhance K‐ion storage in carbonaceous materials. One shortcoming is the lack of precise control over producing the edge‐nitrogen configuration. Here, a molecular‐scale copolymer pyrolysis strategy is used to precisely control edge‐nitrogen doping in carbonaceous materials. This process results in defect‐rich, edge‐nitrogen doped carbons (ENDC) with a high nitrogen‐doping level (up to 10.5 at %) and a high edge‐nitrogen ratio (87.6 %). The optimized ENDC exhibits a high reversible capacity of 423 mAh g−1, a high initial Coulombic efficiency of 65 %, superior rate capability, and long cycle life (93.8 % retention after three months). This strategy can be extended to design other edge‐heteroatom‐rich carbons through pyrolysis of copolymers for efficient storage of various mobile ions.

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“…However, the larger ionic radius and sluggish kinetics of Na raise difficulties for the construction of SIBs with high energy/power densities and long lifespan. Therefore, it is paramount to exploit advanced host materials with a large framework with abundant ion channels …”

Section: Introductionmentioning

confidence: 99%

High‐Performance Manganese Hexacyanoferrate with Cubic Structure as Superior Cathode Material for Sodium‐Ion Batteries

Tang

¹

,

Li

²

,

Feng

³

et al. 2020

Adv Funct Materials

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Sodium manganese hexacyanoferrate (NaxMnFe(CN)6) is one of the most promising cathode materials for sodium‐ion batteries (SIBs) due to the high voltage and low cost. However, its cycling performance is limited by the multiple phase transitions during Na+ insertion/extraction. In this work, a facile strategy is developed to synthesize cubic and monoclinic structured NaxMnFe(CN)6, and their structure evolutions are investigated through in situ X‐ray diffraction (XRD), ex situ Raman, and X‐ray photoelectron spectroscopy (XPS) characterizations. It is revealed that the monoclinic phase undergoes undesirable multiple two‐phase reactions (monoclinic ↔ cubic ↔ tetragonal) due to the large lattice distortions caused by the Jahn–Teller effects of Mn3+, resulting in poor cycling performances with 38% capacity retention. The cubic NaxMnFe(CN)6 with high structural symmetry maintains the structural stability during the repeated Na+ insertion/extraction process, demonstrating impressive electrochemical performances with specific capacity of ≈120 mAh g−1 at 3.5 V (vs Na/Na+), capacity retention of ≈70% over 500 cycles at 200 mA g−1. In addition, the TiO2//C‐MnHCF full battery is fabricated with an energy density of 111 Wh kg−1, suggesting the great potential of cubic NaxMnFe(CN)6 for practical energy storage applications.

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Hard carbons for sodium-ion batteries: Structure, analysis, sustainability, and electrochemistry

Cited by 584 publications

References 165 publications

A Site‐Selective Doping Strategy of Carbon Anodes with Remarkable K‐Ion Storage Capacity

A Site‐Selective Doping Strategy of Carbon Anodes with Remarkable K‐Ion Storage Capacity

A Site‐Selective Doping Strategy of Carbon Anodes with Remarkable K‐Ion Storage Capacity

High‐Performance Manganese Hexacyanoferrate with Cubic Structure as Superior Cathode Material for Sodium‐Ion Batteries

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