Carbon Nanofoam-Based Cathodes for Li–O₂Batteries: Correlation of Pore–Solid Architecture and Electrochemical Performance

Abstract

Freestanding, binder-free carbon nanofoam papers afford the opportunity to gauge the influence of pore size on the discharge capacity of Li–O2 cells. Four sets of carbon nanofoam papers were synthesized from resorcinol–formaldehyde sols, with pore size distributions in pyrolyzed forms ranging from mesopores (5–50 nm) to a size regime not represented in the literature for Li-O2 cathodes—small macropores (50–200 nm). The first-cycle discharge capacity in cells containing 0.1 M LiClO4 in dipropylene glycol dimethyl ether tracks the average pore size distribution in the carbon nanofoam cathode, rather than the specific surface area of the nanoscale carbon network or its total pore volume. The macroporous nanofoams yield cathode specific capacity of 1000–1250 mA h g−1 at –0.1 mA cm−2 discharge rate, approximately twice that of the mesoporous nanofoams (∼580–670 mA h g−1), even though the macroporous foams have lower specific surface areas (270 and 375 vs. >400 m2 g−1). The specific capacity of the cathode decreases as the thickness of macroporous carbon nanofoam paper is increased from 180- to 530-μm, which indicates that the interior pore volume is underutilized, particularly with thicker nanofoams. For the four pore–solid nanofoam architectures studied, the specific capacity is limited by pore occlusion arising from solid Li2O2 product that is electrogenerated near the outer boundaries of the nanofoams.

Nanotechnology enabled rechargeable Li–SO2 batteries: another approach towards post-lithium-ion battery systems

“…3c). Our understanding of the relationship between the carbon properties and electrochemical performance of the Li−SO 2 batteries seems to agree well with prior discussions by Chervin et al 20 To gain further insights into the electrochemical performance of the Li−SO 2 cells with respect to the type of nanostructured carbon materials, we observed the microstructural changes of some carbon cathodes during the discharge and charge processes using SEM. S2b), the carbon materials with a pore size in the range of 20−120 nm, such as KB-600JD, rGO, and OMC, show higher capacities than other carbon materials.…”

A RuO2 nanoparticle-decorated buckypaper cathode for non-aqueous lithium–oxygen batteries

“…[7][8][9][10][11][12] A typical non-aqueous lithium-oxygen battery consists of a lithium metal anode, a lithium ion conducting electrolyte, and a porous cathode. During discharge, oxygen is taken from ambient air and reduced at the porous cathode to form the discharge product lithium peroxide (Li 2 O 2 ).…”

Diamond-Like Carbon Nanofoam from Low-Temperature Hydrothermal Carbonization of a Sucrose/Naphthalene Precursor Solution

“…Porous carbon structures have also been produced by HTC of crude plant material, which can be up-scaled to large quantities with low cost, and these materials may have industrial applications for catalytic support and for sorption purposes [11]. Other potential applications of carbon nanofoam include hydrogen storage [12], cathodes for batteries [13,14] or composites for electrodes [15,16]. It follows that the HTC method for the synthesis of functional carbon materials can be used for a broad range of applications [2].…”