Incommensurate Graphene Foam as a High Capacity Lithium Intercalation Anode

Abstract

Graphite’s capacity of intercalating lithium in rechargeable batteries is limited (theoretically, 372 mAh g−1) due to low diffusion within commensurately-stacked graphene layers. Graphene foam with highly enriched incommensurately-stacked layers was grown and applied as an active electrode in rechargeable batteries. A 93% incommensurate graphene foam demonstrated a reversible specific capacity of 1,540 mAh g−1 with a 75% coulombic efficiency, and an 86% incommensurate sample achieves above 99% coulombic efficiency exhibiting 930 mAh g−1 specific capacity. The structural and binding analysis of graphene show that lithium atoms highly intercalate within weakly interacting incommensurately-stacked graphene network, followed by a further flexible rearrangement of layers for a long-term stable cycling. We consider lithium intercalation model for multilayer graphene where capacity varies with N number of layers resulting LiN+1C2N stoichiometry. The effective capacity of commonly used carbon-based rechargeable batteries can be significantly improved using incommensurate graphene as an anode material.

Understanding Excess Li Storage beyond LiC6 in Reduced Dimensional Scale Graphene

“…Considering the peak characteristics concerning C and O for fresh and cycled, the symmetry of the peak is distinct for the cycled ones, and the corresponding deconvoluted results (Figure e,f) expose the contributions from several species formed with C and O such as CO, CO, OCO, and COC groups reminiscent from the decomposition of the organic solvent with Li to form unstable alkyl lithium carbonates like Li 2 CO 3 and ROCO 2 Li. In addition, the O 1s spectrum exposes the contributions from ROLi and Li x PF y O z species due to the reaction between the LiPF 6 salt and the solvent. , The Li 1s peak is evident at a binding energy (BE) of 56 eV, which corresponds to the formation of only LiC x species, and to be specific, the absence of any peak at BE of 55.2 eV representing the metallic Li excludes the occurrence of metallic Li due to deposition. − …”

Tracing the Bioavailability of Three-Dimensional Graphene Foam in Biological Tissues

“…The G peak is the E2g optical mode of graphite and this band arises from the C=C in-plane stretching vibration. Negligible effect of the D mode at ≈1300 cm −1 indicates a perfect crystal structure of the foam, and a carbon monolithic-like structure [ 16 , 17 , 18 , 19 ]. As shown, the G peak (intensity: I G ) is stronger than the 2D peak (intensity: I 2D ), suggesting the few layer feature of the GF (I G /I 2D ~ 2.4).…”

Allylimidazolium-Based Poly(ionic liquid) Anodic Binder for Lithium-Ion Batteries with Enhanced Cyclability

“…Since the discovery of reversible intercalation of lithium ions in graphite anodes by Yazami et al, a variety of electrode materials and electrolytes were designed to enhance the performance and safety. Most of the anodes can be categorized as intercalation-based (carbonaceous materials like graphite, graphene foam, carbon nanotubes, porous carbon, etc., and titanium oxides like TiO 2 and LiTi 4 O 5 − ), alloy-based (silicon, tin, germanium − ), and conversion materials (metal oxides of iron, molybdenum, copper etc). Similarly, a plethora of cathode materials are available with structural and compositional diversity.…”