Interfacial Li-ion localization in hierarchical carbon anodes

Abstract

An understanding of the nanoscale structure and energetics of carbon composites is critical for their applications in electric energy storage. Here, we study the properties of carbon anodes synthesized from low-cost renewable lignin biopolymers for use in energy storage applications such as Li-ion batteries. The anodes possess both nanoscale and mesoscale order, consisting of carbon nanocrystallites distributed within an amorphous carbon matrix. Molecular dynamics simulations of an experimentally validated model of the anode is used to elucidate the nature of Li-ion storage. We report the discovery of a novel mechanism of Li-ion storage, one in which Li + is not intercalated between layers of carbon (as is the case in graphitic anodes), but rather is localized at the interface of crystalline carbon domains. In particular, the effects of Liion binding energy on the Li-Li, Li-H, and Li-C pair distribution functions are revealed, along with the effect on charge distribution. Lastly, the atomic environments surrounding the Li-ions

Increasing the revenue from lignocellulosic biomass: Maximizing feedstock utilization

“…This lignin stream could also be used to produce other high–surface area carbon products that can be used in a variety of energy storage applications [that is, supercapacitors ( 20 ), battery anodes ( 5 ), and gas storage ( 21 )], functional carbon products, or, as recently demonstrated, lignin monomers ( 22 ). The use of lignin as a carbon feedstock for battery anode material shows considerable promise because its nanographitic carbon structure is stable, with high theoretical and experimental stability and performance compared to natural flake graphite ( 5 , 23 ). Carbons derived from GVL-fractionated lignin demonstrate similar nanographitic domains with a higher crystallinity (fig.…”

Combining Experimental and Theoretical Techniques to Gain an Atomic Level Understanding of the Defect Binding Mechanism in Hard Carbon Anodes for Sodium Ion Batteries

“…[78] A Lennard-Jones potential yielded an atomic interaction of Na and C as opposed to the more representative ionic interaction of Na + and C x − , which could be approximated using reactive potentials. [27][28][29][30] However, in light of other modeling of Na binding mechanisms in HC, its use was a straightforward approach which enabled the authors' detailed structural analysis in a dilute Na-C x model. [29] Although random, the initial position of the Na probe atom was restricted to being further than 1.0 Å from every carbon atom and <1.8 Å from the nearest carbon atom.…”

“…However, the same analysis shows it does not impact the Na binding mechanism. [27][28][29][30] The interaction between a model which has been appropriately decorated with heteroatoms and would afford an opportunity to study electrochemistry in HCs further and should be pursued.…”

“…procedures to understand electrochemical processes such as capacitance [24][25][26] and Li-ion binding, [27][28][29][30] but there are few studies that examine in sufficient detail, the structure of HC in relation to Na-ion binding. [29,30] In this study, we synthesized dense, low porosity HC materials derived from sucrose in line with our previous work.…”

A Bayesian Framework for Persistent Homology

“…This is problematic as APT may have a spatial resolution approximately the length of the unit cell under consideration [28,42]. Hence, the process is unable to see the finer details of a material, rendering the determination of a lattice structure a challenging problem [38,55]. Existing algorithms for detecting the crystal structure [13,24,25,32,43,56] are not able to establish the crystal lattice of an APT dataset, as they rely on symmetry arguments based on identifying repeating parts of molecules.…”