High‐Pressure Synthesis and Characterization of the Alkali Diazenide Li<sub>2</sub>N<sub>2</sub>

Schneider, Sebastian B.; Frankovsky, Rainer; Schnick, Wolfgang

doi:10.1002/ange.201108252

Cited by 12 publications

(2 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The oxidation of BN 3− 2 can also be viewed as if BN 3− 2 would be a way of storing a nitride ion, N 3− absorbed to a neutral diatomic BN molecule and allowing for the electrochemistry of the N 3− ion within this complex. The N 3− ion represents an oxidation state of N as in ammonia (NH 3 ) or in lithium nitride (Li 3 N), while the oxidized form N 2− is familiar from hydrazine (N 2 H 4 ) and the further oxidized form N − is known from lithium-diazenide (Li 2 N 2 ) 38 . The Li 3 BN 2 molecule may be viewed as a combination of half of a Li 2 N 2 and half of a hydrazine-like Li 4 N 2 through a B atom, whereby the B binds with a double bond to the diazenide-type N and with a single bond to the hydrazine-type N. Albeit oxidized forms of the BN 3− 2 ion, such as BN 2− 2 and BN − 2 have not been reported in the literature yet, there is recent indirect evidence to the existence of BN 2− 2 in Na 2 BN 2 obtained during thermogravimetric analysis of the thermolysis of Na 2 KBN 2 , after the evaporation of all K in a well separable step 39 .…”

Section: Resultsmentioning

confidence: 99%

Ultrahigh energy density Li-ion batteries based on cathodes of 1D metals with –Li–N–B–N– repeating units in α-LixBN2 (1 ⩽ x ⩽ 3)

Németh

2014

The Journal of Chemical Physics

View full text Add to dashboard Cite

Ultrahigh energy density batteries based on α-Li x BN 2 (1≤x≤3) positive electrode materials are predicted using density functional theory calculations. The utilization of the reversible LiBN 2 + 2 Li + + 2 e − Li 3 BN 2 electrochemical cell reaction leads to a voltage of 3.62 V (vs Li/Li + ), theoretical energy densities of 3251 Wh/kg and 5927 Wh/L, with capacities of 899 mAh/g and 1638 mAh/cm 3 , while the cell volume of α-Li 3 BN 2 changes only 2.8 % per two-electron transfer. These values are far superior to the best existing or theoretically designed intercalation or conversion-based positive electrode materials. For comparison, the theoretical energy density of a Li-O 2 /peroxide battery is 3450 Wh/kg (including the weight of O 2 ), that of a Li-S battery is 2600 Wh/kg, that of Li 3 Cr(BO 3 )(PO 4 ) (one of the best designer intercalation materials) is 1700 Wh/kg, while already commercialized LiCoO 2 allows for 568 Wh/kg. α-Li 3 BN 2 is also known as a good Li-ion conductor with experimentally observed 3 mS/cm ionic conductivity and 78 kJ/mol (≈ 0.8 eV) activation energy of conduction. The attractive features of α-Li x BN 2 (1≤x≤3) are based on a crystal lattice of 1D conjugated polymers with -Li-N-B-N-repeating units. When some of the Li is deintercalated from α-Li 3 BN 2 the crystal becomes a metallic electron conductor, based on the underlying 1D conjugated π electron system. Thus α-Li x BN 2 (1≤x≤3) represents a new type of 1D conjugated polymers with great potential for energy storage and other applications. IntroductionThere is a quest for materials that would allow for storing large amounts of energy per unit weight and volume and can be utilized as electroactive species in electrochemical energy storage devices. These materials typically serve as part of the positive electrode of batteries while negative electrodes may be composed of bulk metals, such as Li, Na, Mg, Al, etc, or as electrically and ionically conductive composite materials containing these metals. The driving force of the discharge process in batteries is the chemical potential difference of electrons and mobile cations in the positive and negative electrodes manifesting as voltage between the current collectors. Main stream battery research focuses on improving Li-ion batteries that are based on positive electrode materials capable of intercalating/deintercalating Li + ions during the charge/discharge processes. . In practice, these values are far smaller due to additional materials that are needed for practical implementations of the corresponding electrochemistries. For example, best realized Li-S batteries allow for 300-500 Wh/kg 3 which is still significantly better than that of commercially available batteries (130-200 Wh/kg, based on LiMO 2 ). For intercalationbased cathode materials there is typically a factor of 3-4 difference between the theoretical and practical energy density values. Research is also conducted on metal-air type batteries that have extremely large theoretical energy densities. A rechargeable Li-O 2 /peroxi...

show abstract

Section: Resultsmentioning

confidence: 99%

Ultrahigh energy density Li-ion batteries based on cathodes of 1D metals with –Li–N–B–N– repeating units in α-LixBN2 (1 ⩽ x ⩽ 3)

Németh

2014

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…synthesized binary diazenides SrN 2 and BaN 2 , proving the existence of the homonuclear dinitrogen anion N 2 2− , which is a deprotonated diazene N 2 H 2 with a NN bond. Recently, Schnick et al 12. experimentally confirmed the stability of the first alkali diazenide Li 2 N 2 under high pressure/high temperature (HP/HT) conditions.…”

mentioning

confidence: 99%

All‐Nitrogen Analogue of Ozone: Li₃N₃ Species

Olson¹,

Ivanov²,

Boldyrev³

2014

Chemistry A European J

View full text Add to dashboard Cite

A theoretical study of ozone isoelectronic Li3N3 species has been performed. Ab initio electronic structure calculations prove the viability of the ozone-like Li3N3 molecule that might become synthesized. The predicted Li3N3 species with a novel N3(3-) molecular motif possess structural and chemical bonding features similar to that of O3 molecules and can thus be considered as an "all-nitrogen ozone".

show abstract

Vorhersage stickstoffbasierter Verbindungsklassen: Guanidinate TCN₃ (T=V, Nb, Ta) und Orthonitridocarbonate T′₂CN₄ (T′=Ti, Zr, Hf) von Übergangsmetallen

2020

View full text Add to dashboard Cite

show abstract

High‐Pressure Synthesis and Characterization of the Alkali Diazenide Li₂N₂

Cited by 12 publications

References 52 publications

Ultrahigh energy density Li-ion batteries based on cathodes of 1D metals with –Li–N–B–N– repeating units in α-LixBN2 (1 ⩽ x ⩽ 3)

Ultrahigh energy density Li-ion batteries based on cathodes of 1D metals with –Li–N–B–N– repeating units in α-LixBN2 (1 ⩽ x ⩽ 3)

All‐Nitrogen Analogue of Ozone: Li₃N₃ Species

Vorhersage stickstoffbasierter Verbindungsklassen: Guanidinate TCN₃ (T=V, Nb, Ta) und Orthonitridocarbonate T′₂CN₄ (T′=Ti, Zr, Hf) von Übergangsmetallen

Contact Info

Product

Resources

About

High‐Pressure Synthesis and Characterization of the Alkali Diazenide Li2N2

Cited by 12 publications

References 52 publications

Ultrahigh energy density Li-ion batteries based on cathodes of 1D metals with –Li–N–B–N– repeating units in α-LixBN2 (1 ⩽ x ⩽ 3)

Ultrahigh energy density Li-ion batteries based on cathodes of 1D metals with –Li–N–B–N– repeating units in α-LixBN2 (1 ⩽ x ⩽ 3)

All‐Nitrogen Analogue of Ozone: Li3N3 Species

Vorhersage stickstoffbasierter Verbindungsklassen: Guanidinate TCN3 (T=V, Nb, Ta) und Orthonitridocarbonate T′2CN4 (T′=Ti, Zr, Hf) von Übergangsmetallen

Contact Info

Product

Resources

About

High‐Pressure Synthesis and Characterization of the Alkali Diazenide Li₂N₂

All‐Nitrogen Analogue of Ozone: Li₃N₃ Species

Vorhersage stickstoffbasierter Verbindungsklassen: Guanidinate TCN₃ (T=V, Nb, Ta) und Orthonitridocarbonate T′₂CN₄ (T′=Ti, Zr, Hf) von Übergangsmetallen