Juthaporn Wutthiprom

Chemical Adsorption and Physical Confinement of Polysulfides with the Janus-faced Interlayer for High-performance Lithium-Sulfur Batteries

We design the Janus-like interlayer with two different functional faces for suppressing the shuttle of soluble lithium polysulfides (LPSs) in lithium-sulfur batteries (LSBs). At the front face, the conductive functionalized carbon fiber paper (f-CFP) having oxygen-containing groups i.e., -OH and -COOH on its surface was placed face to face with the sulfur cathode serving as the first barrier accommodating the volume expansion during cycling process and the oxygen-containing groups can also adsorb the soluble LPSs via lithium bonds. At the back face, a crystalline coordination network of [Zn(H2PO4)2(TzH)2]n (ZnPTz) was coated on the back side of f-CFP serving as the second barrier retarding the left LPSs passing through the front face via both physical confinement and chemical adsorption (i.e. Li bonding). The LSB using the Janus-like interlayer exhibits a high reversible discharge capacity of 1,416 mAh g−1 at 0.1C with a low capacity fading of 0.05% per cycle, 92% capacity retention after 200 cycles and ca. 100% coulombic efficiency. The fully charged LSB cell can practically supply electricity to a spinning motor with a nominal voltage of 3.0 V for 28 min demonstrating many potential applications.

Turning Carbon Black to Hollow Carbon Nanospheres for Enhancing Charge Storage Capacities of LiMn2O4, LiCoO2, LiNiMnCoO2, and LiFePO4 Lithium-Ion Batteries

Carbon black nanospheres were turned to hollow carbon nanospheres (HCNs) and were used as the conductive additive in the cathodes of Li-ion batteries (LIBs). The results show that 10 wt % HCN added to the LIB cathodes, such as LiMn2O4, LiCoO2, LiNiMnCoO2, and LiFePO4, can provide significantly higher specific capacity than those using spherical carbon black. For example, a specific capacity of the LiMn2O4/HCN/PVDF cathode at 80:10:10 wt % with a bulk electrical conductivity of 1.07 Ω cm–2 is 125 mA h g–1 at 0.1 C from 3.0 to 4.3 V versus Li+/Li, which is 3.85-fold higher than that using Super P. The stability tested at 1 C remains over 95% after 800 charge/discharge cycles with 100% Coulombic efficiency. Replacing the present carbon black conductive additive with HCN in this work may be one of the best choices to increase the charge storage performance of LIBs rather than only focusing on the development of active cathode materials.

Collaborative design of Li–S batteries using 3D N-doped graphene aerogel as a sulfur host and graphitic carbon nitride paper as an interlayer

Lithium–sulfur batteries (LSBs) have been widely investigated due to their high energy densities; however, their practical applications have still been limited by their poor cycling stability owing to the shuttle mechanism effect, volume expansion, soluble polysulfides, and the poor electrical conductivity of sulfur and Li2S. To address these issues, sulfur was loaded into a conductive 3D nitrogen-doped reduced graphene oxide aerogel (NGae) host with a finely tuned nitrogen doping content. In addition, an interlayer of graphitic carbon nitride coated on flexible and conductive carbon fiber paper (g-C3N4/CFP) was inserted between the cathode and the polymer separator to trap the soluble polysulfides. It was found that the as-fabricated LSB using the NGae host with 4.2% N doping content and the g-C3N4/CFP interlayer can provide a specific capacity of 1271 mA h g−1 at 0.1C with excellent stability over 400 cycles. The capacity fading is rather small (only 0.068% per cycle) while the coulombic efficiency is rather high (ca. 100%). This battery may be practically used in high-energy applications.

Oxidative chemical vapour deposition of a graphene oxide carbocatalyst on 3D nickel foam as a collaborative electrocatalyst towards the hydrogen evolution reaction in acidic electrolyte

In this study, a graphene oxide (GO) carbocatalyst was synthesized as a thin film on a 3D Ni foam substrate (GO@Ni) by oxidative chemical vapour deposition (CVD) using methanol and water as precursors. The GO@Ni was used as a collaborative electrocatalyst towards the hydrogen evolution reaction (HER) in an acidic electrolyte. Notably, pure Ni metal cannot be used as an electrocatalyst in acidic media due to corrosion. The amount of water in the methanol was finely tuned to optimize the electrochemical activity of the GO@Ni for HER. The optimized GO@Ni catalyst, with a sheet resistivity of 133.48 Ω square−1, an optical band gap of 1.52 eV, and a C : O ratio of 3.89 produced using 90 : 10 V% of methanol : water, exhibits excellent and stable HER activity with an overpotential of 137 mV vs. RHE, reaching a high current density of 10 mA cm−2 and prominent electrochemical stability for up to 12 h in 0.5 M H2SO4. In addition, the CVD GO layer on the Ni foam acts as an anti-corrosion material protecting the Ni HER catalyst in the acidic environment. As a result, the GO@Ni may be a promising electrode for HER, replacing expensive Pt catalysts.

Author Correction: Chemical Adsorption and Physical Confinement of Polysulfides with the Janus-faced Interlayer for High-performance Lithium-Sulfur Batteries

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.