Mineralization of Self‐assembled Peptide Nanofibers for Rechargeable Lithium Ion Batteries

Abstract

One of most unique and fascinating features of natural biomineralization processes is the controlled growth and hierarchical organization of inorganic minerals along with organic materials. Such marvels of nature give excellent physicochemical properties to natural biomaterials [1][2][3] and provide inspiration for the synthesis of novel functional nanomaterials to chemists and materials scientists. [4][5][6][7][8][9] For example, natural bones with excellent mechanical properties are a kind of organic/inorganic hybrid materials with organic collagen nanofi brils and inorganic calcium phosphate nanocrystals hierarchically organized on a nanoscale. [ 10 ] Researchers have found that the hierarchical organization of organic and inorganic components of natural biomaterials is due mainly to the repetitive display of acidic functional groups on the surface of organic materials [ 2 , 11 ] that can act as a nucleation site for the growth of inorganic materials. In this regard, numerous efforts have been made to synthesize novel hybrid nanomaterials by mimicking biomineralization processes especially for biomedical applications. [12][13][14][15] For example, Hartgerink and colleagues reported on synthesis and mineralization of peptideamphiphile nanofi bers displaying phosphate groups on their surface for bone regeneration. [ 13 ] To date, however, the synthesis of industrially important hybrid nanomaterials by mimicking biomineralization processes has been rarely reported despite many potential advantages of biomimetic approaches such as environmental compatibility and high controllability of shape and size.On the other hand, interest is growing in the fabrication of functional nanomaterials by self-assembly of peptide-based building blocks because of functional fl exibility and environmental compatibility. [ 16 , 17 ] Among numerous self-assembling peptides reported to date, diphenylalanine (Phe-Phe, FF) and its derivatives [18][19][20][21][22][23][24][25][26][27][28][29][30] are simplest peptides exhibiting unique mechanical, [ 19 ] electrochemical, [ 20 ] and optical properties [ 21 ] as well as high thermal and chemical stabilities. [ 23 ] It has been reported that they can readily form various nanostructures, including nanotubes, [18][19][20][21][22] nanowires, [23][24][25][26][27] nanospheres, [ 28 ] organogels, [ 29 ] and hydrogels [ 30 ] through a self-assembly process. Here, we fi rst report the synthesis of transition metal phosphate nanotubes for application as a cathode material for rechargeable lithium (Li) ion batteries by using a peptide hydrogel self-assembled from fl uorenylmethoxycarbonyl (Fmoc)-FF [ 30 ] as a template. The peptide hydrogel is composed of very thin nanofi bers (diameter about a few tens of nm) and displays numerous acidic and polar moieties on its surface (Figures S1 and S2 in the Supporting Information), which are highly benefi cial for the synthesis of novel organic/inorganic hybrid nanomaterials.We synthesized peptide/transition metal phosphate core/ shell nanofi bers, as schematic...

Bio-Inspired Synthesis of Electrode Materials for Lithium Rechargeable Batteries

“…Similarly, separate injections of an aqueous solution of Fe 3+ and another solution of PO 4 3-are believed to result in conformal coating of amorphous FePO 4 . Peptide molecules (Fmocdiphenylalanine; Figure 22(b)), are assembled into the network in H 2 O, as depicted in Figure 22(c-d) (Ryu et al 2010a). The peptide hydrogel is formed in a filtration apparatus, and then the solution of Fe 3+ is injected and stored inside the apparatus for adsorption of Fe 3+ ions onto the peptide surface.…”

“…Electrochemical properties of a TiO 2 nanotube network: (a) discharge-charge profiles at a current rate of C/5 (inset: differential capacity curve at the first cycle), (b) high rate capability compared with conventional TiO 2 nanoparticles, and (c) capacity retention and Coulombic efficiency at a current rate of 1C (1C = 335.45 mAh g-1) . (Ryu et al 2010a). Interestingly, other transition metal phosphates also could be coated onto the peptide assembly by the same method as shown in Figure 23 (Ryu et al 2010a).…”

“…In this respect, an aqueous solution-based mineralization technique can be advantageous in fabricating the nanotube network structure. Figure 22(a) simply describes the process for the synthesis of the network structure based on the sequential adsorption method using aqueous solution (Ryu et al 2010a). An amorphous FePO 4 cathode is chosen as a coating material because Fe 3+ and PO 4 3-ions are dissolved readily in H 2 O.…”

“…Biomaterials, whose varieties of nanostructures are easily obtained by simple control of the synthesis conditions, are considered useful structural templates for nanofabrication (Cui et al, 2010). Also, their surface groups can offer possible nucleation sites for the growth of electrode materials (Ryu et al, 2010a). Nanostructured electrode materials based on biomaterial templates can show improved electrochemical performance compared with that of bulk materials, and their fabrication processes are often more environmentally friendly compared with other methods of preparing nanomaterials.…”

Synthesis Processes for Li-Ion Battery Electrodes – From Solid State Reaction to Solvothermal Self-Assembly Methods

“…The latest trend in battery materials processing is using biomineralization process in order to build controlled nanoarchitectured compounds under ambient conditions [Ryu, J. et al (2010)]. Biomimetic chemistry involves the utilization of actual biomolecular entities such as proteins, bacteria and viruses to act either as a growth medium or as a spatially constrained nanoscale reactor for the generation of nanoparticles.…”