Bismuth germanate (Bi4Ge3O12), a promising high-capacity lithium-ion battery anode

2018 ◽  
Vol 54 (81) ◽  
pp. 11483-11486 ◽  
Author(s):  
Jassiel R. Rodriguez ◽  
Carlos Belman-Rodriguez ◽  
Sergio A. Aguila ◽  
Yanning Zhang ◽  
Hongxian Liu ◽  
...  
Keyword(s):  
Density Functional ◽  
High Capacity ◽  
Lithium Ion ◽  
Density Functional Theory Calculations ◽  
Reversible Capacity ◽  
Functional Theory ◽  
Tap Density ◽  
Micron Size ◽  
A Current ◽  
Battery Anode

Cubic Bi4Ge3O12 lithiation-host electrode material with micron size, low surface area (3 m2 g−1) and high tap density yielded a reversible capacity of 586 mA h g−1 at a current density of 200 mA g−1 after 500 charge–discharge cycles. Density functional theory calculations detected distorted [BiO6]9− octahedra with two types of Bi–O bonds.

scholarly journals Exposing unsaturated Cu1-O2 sites in nanoscale Cu-MOF for efficient electrocatalytic hydrogen evolution

2021 ◽  
Vol 7 (18) ◽  
pp. eabg2580
Author(s):  
Weiren Cheng ◽  
Huabin Zhang ◽  
Deyan Luan ◽  
Xiong Wen (David) Lou
Keyword(s):  
Hydrogen Evolution ◽  
Density Functional ◽  
Metal Organic Framework ◽  
Density Functional Theory Calculations ◽  
Active Centers ◽  
Functional Theory ◽  
Hollow Nanostructure ◽  
Metal Organic ◽  
X Ray Absorption ◽  
A Current

Conductive metal-organic framework (MOF) materials have been recently considered as effective electrocatalysts. However, they usually suffer from two major drawbacks, poor electrochemical stability and low electrocatalytic activity in bulk form. Here, we have developed a rational strategy to fabricate a promising electrocatalyst composed of a nanoscale conductive copper-based MOF (Cu-MOF) layer fully supported over synergetic iron hydr(oxy)oxide [Fe(OH)x] nanoboxes. Owing to the highly exposed active centers, enhanced charge transfer, and robust hollow nanostructure, the obtained Fe(OH)x@Cu-MOF nanoboxes exhibit superior activity and stability for the electrocatalytic hydrogen evolution reaction (HER). Specifically, it needs an overpotential of 112 mV to reach a current density of 10 mA cm−2 with a small Tafel slope of 76 mV dec−1. X-ray absorption fine structure spectroscopy combined with density functional theory calculations unravels that the highly exposed coordinatively unsaturated Cu1-O2 centers could effectively accelerate the formation of key *H intermediates toward fast HER kinetics.

scholarly journals Gold Nanoclusters Grown on MoS2 Nanosheets by Pulsed Laser Deposition: An Enhanced Hydrogen Evolution Reaction

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7503
Author(s):  
Yuting Jing ◽  
Ruijing Wang ◽  
Qiang Wang ◽  
Xuefeng Wang
Keyword(s):  
Active Sites ◽  
Density Functional ◽  
Au Nanoparticles ◽  
Gold Nanoclusters ◽  
Density Functional Theory Calculations ◽  
Laser Deposition ◽  
Mos2 Nanosheets ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
A Current

Au nanoparticles were decorated on a 2H MoS2 surface to form an Au/MoS2 composite by pulse laser deposition. Improved HER activity of Au/MoS2 is evidenced by a positively shifted overpotential (−77 mV) at a current density of −10 mA cm−2 compared with pure MoS2 nanosheets. Experimental evidence shows that the interface between Au and MoS2 provides more sites to combine protons to form an active H atom. The density functional theory calculations found that new Au active sites on the Au and MoS2 interface with improved conductivity of the whole system are essential for enhancing HER activity of Au/MoS2.

scholarly journals Evidence for a Solid-Electrolyte Inductive Effect in Superionic Conductors

2020 ◽  
Author(s):  
Sean Culver ◽  
Alex Squires ◽  
Nicolo Minafra ◽  
Callum Armstrong ◽  
Thorben Krauskopf ◽  
...  
Keyword(s):  
Solid Electrolyte ◽  
Solid Electrolytes ◽  
Density Functional ◽  
Inductive Effect ◽  
Ionic Conductivities ◽  
Lithium Ion ◽  
Density Functional Theory Calculations ◽  
Ion Diffusion ◽  
Functional Theory ◽  
Li Ion

<p>Identifying and optimizing highly-conducting lithium-ion solid electrolytes is a critical step towards the realization of commercial all–solid-state lithium-ion batteries. Strategies to enhance ionic conductivities in solid electrolytes typically focus on the effects of modifying their crystal structures or of tuning mobile-ion stoichiometries. A less-explored approach is to modulate the chemical-bonding interactions within a material to promote fast lithium-ion diffusion. Recently, the idea of a solid-electrolyte inductive effect was proposed, whereby changes in bonding within the solid-electrolyte host-framework modify the potential-energy landscape for the mobile ions, resulting in an enhanced ionic conductivity. This concept has since been invoked to explain anomalous conductivity trends in a number of solid electrolytes. Direct evidence for a solid-electrolyte inductive effect, however, is lacking—in part because of the challenge of quantifying changes in local bonding interactions within a solid-electrolyte host-framework. <a></a><a>Here, we consider the evidence for a solid-electrolyte inductive effect in the archetypal superionic lithium-ion conductor Li<sub>10</sub>Ge<sub>1−<i>x</i></sub>Sn<i><sub>x</sub></i>P<sub>2</sub>S<sub>12</sub>, using Rietveld refinements against high-resolution temperature-dependent neutron-diffraction data, Raman spectroscopy, and density functional theory calculations.</a> Substituting Ge for Sn weakens the {Ge,Sn}–S bonding interactions and increases the charge-density associated with the S<sup>2-</sup> ions. This charge redistribution modifies the Li<sup>+</sup> substructure causing Li<sup>+</sup> ions to bind more strongly to the host-framework S anions; which in turn modulates the Li-ion potential-energy surface, increasing local barriers for Li-ion diffusion. Each of these effects is consistent with the predictions of the solid-electrolyte inductive effect model. Density functional theory calculations further predict that this inductive effect occurs even in the absence of changes to the host-framework geometry due to Ge → Sn substitution. These results provide direct evidence in support of a measurable solid-electrolyte inductive effect and demonstrate its application as a practical strategy for tuning ionic conductivities in superionic lithium-ion conductors.</p>

scholarly journals Nanometer-size Na cluster formation in micropore of hard carbon as origin of higher-capacity Na-ion battery

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yong Youn ◽  
Bo Gao ◽  
Azusa Kamiyama ◽  
Kei Kubota ◽  
Shinichi Komaba ◽  
...  
Keyword(s):  
Density Functional ◽  
Cluster Formation ◽  
High Capacity ◽  
Density Functional Theory Calculations ◽  
High Energy ◽  
High Energy Density ◽  
Hard Carbon ◽  
Functional Theory ◽  
Nanometer Size ◽  
Li Ion

AbstractDevelopment of high-energy-density anode is crucial for practical application of Na-ion battery as a post Li-ion battery. Hard carbon (HC), though a promising anode candidate, still has bottlenecks of insufficient capacity and unclear microscopic picture. Usage of the micropore has been recently discussed, however, the underlying sodiation mechanism is still controversial. Herein we examined the origin for the high-capacity sodiation of HC, based on density functional theory calculations. We demonstrated that nanometer-size Na cluster with 3–6 layers is energetically stable between two sheets of graphene, a model micropore, in addition to the adsorption and intercalation mechanisms. The finding well explains the extended capacity over typical 300 mAhg−1, up to 478 mAhg−1 recently found in the MgO-templated HC. We also clarified that the MgO-template can produce suitable nanometer-size micropores with slightly defective graphitic domains in HC. The present study considerably promotes the atomistic theory of sodiation mechanism and complicated HC science.

scholarly journals Structure-property relationships in organic battery anode materials: exploring redox reactions in crystalline Na- and Li-benzene diacrylate using combined crystallography and density functional theory calculations

2021 ◽  
Author(s):  
Rodrigo Carvalho ◽  
Cleber Marchiori ◽  
Viorica-Alina Oltean ◽  
Stéven Renault ◽  
Tom Willhammar ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Anode Materials ◽  
Redox Reactions ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Structure Property ◽  
Functional Theory ◽  
Structure Property Relationships ◽  
New Generation ◽  
Battery Anode

Organic-based materials are potential candidates for a new generation of sustainable and environmentally friendly battery technologies, but insights are currently missing into the structural, kinetic and thermodynamic properties of how...

scholarly journals Evidence for a Solid-Electrolyte Inductive Effect in Superionic Conductors

2020 ◽  
Author(s):  
Sean Culver ◽  
Alex Squires ◽  
Nicolo Minafra ◽  
Callum Armstrong ◽  
Thorben Krauskopf ◽  
...  
Keyword(s):  
Solid Electrolyte ◽  
Solid Electrolytes ◽  
Density Functional ◽  
Inductive Effect ◽  
Ionic Conductivities ◽  
Lithium Ion ◽  
Density Functional Theory Calculations ◽  
Ion Diffusion ◽  
Functional Theory ◽  
Li Ion

<p>Identifying and optimizing highly-conducting lithium-ion solid electrolytes is a critical step towards the realization of commercial all–solid-state lithium-ion batteries. Strategies to enhance ionic conductivities in solid electrolytes typically focus on the effects of modifying their crystal structures or of tuning mobile-ion stoichiometries. A less-explored approach is to modulate the chemical-bonding interactions within a material to promote fast lithium-ion diffusion. Recently, the idea of a solid-electrolyte inductive effect was proposed, whereby changes in bonding within the solid-electrolyte host-framework modify the potential-energy landscape for the mobile ions, resulting in an enhanced ionic conductivity. This concept has since been invoked to explain anomalous conductivity trends in a number of solid electrolytes. Direct evidence for a solid-electrolyte inductive effect, however, is lacking—in part because of the challenge of quantifying changes in local bonding interactions within a solid-electrolyte host-framework. <a></a><a>Here, we consider the evidence for a solid-electrolyte inductive effect in the archetypal superionic lithium-ion conductor Li<sub>10</sub>Ge<sub>1−<i>x</i></sub>Sn<i><sub>x</sub></i>P<sub>2</sub>S<sub>12</sub>, using Rietveld refinements against high-resolution temperature-dependent neutron-diffraction data, Raman spectroscopy, and density functional theory calculations.</a> Substituting Ge for Sn weakens the {Ge,Sn}–S bonding interactions and increases the charge-density associated with the S<sup>2-</sup> ions. This charge redistribution modifies the Li<sup>+</sup> substructure causing Li<sup>+</sup> ions to bind more strongly to the host-framework S anions; which in turn modulates the Li-ion potential-energy surface, increasing local barriers for Li-ion diffusion. Each of these effects is consistent with the predictions of the solid-electrolyte inductive effect model. Density functional theory calculations further predict that this inductive effect occurs even in the absence of changes to the host-framework geometry due to Ge → Sn substitution. These results provide direct evidence in support of a measurable solid-electrolyte inductive effect and demonstrate its application as a practical strategy for tuning ionic conductivities in superionic lithium-ion conductors.</p>

scholarly journals Real-time imaging of Na+ reversible intercalation in “Janus” graphene stacks for battery applications

2021 ◽  
Vol 7 (22) ◽  
pp. eabf0812
Author(s):  
Jinhua Sun ◽  
Matthew Sadd ◽  
Philip Edenborg ◽  
Henrik Grönbeck ◽  
Peter H. Thiesen ◽  
...  
Keyword(s):  
Density Functional ◽  
Lithium Ion ◽  
Density Functional Theory Calculations ◽  
Rechargeable Batteries ◽  
Functional Theory ◽  
Imaging Ellipsometry ◽  
Ionic Bonds ◽  
Abundant Element ◽  
Sodium Storage ◽  
Uniform Pore Size

Sodium, in contrast to other metals, cannot intercalate in graphite, hindering the use of this cheap, abundant element in rechargeable batteries. Here, we report a nanometric graphite-like anode for Na+ storage, formed by stacked graphene sheets functionalized only on one side, termed Janus graphene. The asymmetric functionalization allows reversible intercalation of Na+, as monitored by operando Raman spectroelectrochemistry and visualized by imaging ellipsometry. Our Janus graphene has uniform pore size, controllable functionalization density, and few edges; it can store Na+ differently from graphite and stacked graphene. Density functional theory calculations demonstrate that Na+ preferably rests close to -NH2 group forming synergic ionic bonds to graphene, making the interaction process energetically favorable. The estimated sodium storage up to C6.9Na is comparable to graphite for standard lithium ion batteries. Given such encouraging Na+ reversible intercalation behavior, our approach provides a way to design carbon-based materials for sodium ion batteries.

MX (M = Ge, Sn; X = S, Se) sheets: theoretical prediction of new promising electrode materials for Li ion batteries

2016 ◽  
Vol 4 (28) ◽  
pp. 10906-10913 ◽  
Author(s):  
Yungang Zhou
Keyword(s):  
Density Functional Theory ◽  
High Performance ◽  
Density Functional ◽  
Electrode Materials ◽  
Lithium Ion ◽  
Density Functional Theory Calculations ◽  
Two Dimensional ◽  
Li Ion Batteries ◽  
Functional Theory ◽  
Li Ion

In this work, via density functional theory calculations, we explored the interaction of Li with recently synthesized two-dimensional structures, MX (M = Ge, Sn; X = S, Se) sheets, for application in high-performance lithium ion batteries.

Sign in / Sign up

Export Citation Format

Share Document