Biotemplating pores with size and shape diversity for Li-oxygen Battery Cathodes

Abstract

Synthetic porogens provide an easy way to create porous structures, but their usage is limited due to synthetic difficulties, process complexities and prohibitive costs. Here we investigate the use of bacteria, sustainable and naturally abundant materials, as a pore template. The bacteria require no chemical synthesis, come in variable sizes and shapes, degrade easier and are approximately a million times cheaper than conventional porogens. We fabricate free standing porous multiwalled carbon nanotube (MWCNT) films using cultured, harmless bacteria as porogens, and demonstrate substantial Li-oxygen battery performance improvement by porosity control. Pore volume as well as shape in the cathodes were easily tuned to improve oxygen evolution efficiency by 30% and double the full discharge capacity in repeated cycles compared to the compact MWCNT electrode films. The interconnected pores produced by the templates greatly improve the accessibility of reactants allowing the achievement of 4,942 W/kg (8,649 Wh/kg) at 2 A/ge (1.7 mA/cm2).

Iron Nitride@C Nanocubes Inside Core–Shell Fibers to Realize High Air-Stability, Ultralong Life, and Superior Lithium/Sodium Storages

“…C 1s spectra were separated into four peaks corresponding to the C–C, C–OH, CO, and C–N bands, respectively. The functional oxygen group is associated with the carbonization of the organic polymer, which will increase the surface wettability of the electrode . The N 1s spectrum can be deconvolved into three peaks, including pyridinic N, pyrrolic N, and graphic N (Figure e).…”

“…The functional oxygen group is associated with the carbonization of the organic polymer, which will increase the surface wettability of the electrode. 39 The N 1s spectrum can be deconvolved into three peaks, including pyridinic N, pyrrolic N, and graphic N (Figure 3e). The majority of the pyridine N peak suggests that the N element not only contributes to the Fe 2 N phase but also ensures N-doping in the carbon substrate for the CSHN sample.…”

Spray-Printed and Self-Assembled Honeycomb Electrodes of Silicon-Decorated Carbon Nanofibers for Li-Ion Batteries

“…To address these constraints, new approaches to produce micron-scale porous structures with more efficient integration of active materials, conductivity enhancers, and binders have been proposed. For example, template-assisted methods offer excellent control over pore size and morphology but fabricating and then removing the fine-scale featured sacrificial templates can cause problems for cost and scalability and volumetric capacity tends to be unhelpfully low. − Lithographic technologies based on ultraviolet light irradiation and/or ion etching processes allow pore fraction, shape, and alignment to be controlled with micron resolution but require inherently high-cost fabrication apparatus. − Thus, there remains an opportunity for manufacturing approaches that allow improved and more flexible micron-scale pore engineering in LIB electrodes and that have the potential for cost-effective scalability.…”

Unraveling the Significance of Li+/e−/O2 Phase Boundaries with a 3D‐Patterned Cu Electrode for Li–O2 Batteries

“…Although the effect of macropores in electrodes on electrochemical performance has not been clear yet, the proposed pore size of 200-300 nm is in good agreement with previous studies of porous electrodes for Li-O 2 batteries as a representative of submicron-scale pore sizes. [23,29,30] Furthermore, the 3D nanostructured electrode can realize superhydrophobic surface properties by a nanometer-scale surface morphology not seen with Cu foam electrodes. In Table S1 (Supporting Information), the contact angle between the liquid/air/electrode was measured with deionized (DI) water and the electrolyte.…”