Linking to the S element hybrid strategies, S-doped carbon materials having different macrostructures and defect concentrations are prepared by using sulfur and coal-tar-pitch as raw materials in a carbonization temperature range of 700–1000 °C. The evaluations of macrostructure and surface characteristics are performed through XRD, TEM, Raman and XPS measurements. Through the linear fitting among the Na⁺ storage capacity with I_D/I_G and d₀₀₂ values, the correlations of Na⁺ storage capacity with macrostructures and defects are respectively investigated in detail. It is observed that S-doped carbon materials exhibit storage capacity at 120 mAh/g after the charge-discharge is being carried out 2000 cycles at 2.0 A/g. Studies have shown that adsorptions of introduced defects on graphene-like carbon sheets mainly play the role to enhance the storage capacity, and the expanded carbonaceous lamellar spaces of highly disordered and pseudo-graphitic macrostructures provide the channels for fast transfer of Na⁺. Our studies are able to provide references for designs and fabrications of coal tar pitch based soft carbon materials as sodium-ion batteries (SIBs) anodes when using heteroatoms doping methods.

High efficiency conversion of CO₂ can be realized in a solid oxide electrolysis cell. In this work, a flat-tube cell with symmetrical structure supported by Ni-YSZ fuel electrode was used to study the performance of high-temperature CO₂ electrolysis under different reducing gas components in the fuel electrode. The results indicated that in the H₂-CO₂ fuel electrode atmosphere, the instantaneous performance of CO₂ electrolysis is better, the polarization impedance is smaller, and the overpotential of CO₂ electrolysis is lower under the same partial pressure of oxygen (i.e., with the same open-circuit voltage). Compared with CO as the protective gas, it is easier to achieve a stable electrolytic voltage for the electrolysis of CO₂ under H₂ protection. In the H₂-CO₂ reaction atmosphere, when the proportion of protective H₂ increased from 25% to 75%, devastating irreversible degradation occurs at −300 mA/cm², while in the CO-CO₂ (71.7% CO-28.3% CO₂) reaction atmosphere, the similar degradation occurs at – 200 mA/cm². At – 200 mA/cm² constant-current electrolysis, the highest energy conversion efficiency can reach 171% (disregarding energy consumption for heating the gas) and 81.6% (disregarding energy consumption for heating air). This work provides a useful reference for the selection of atmosphere protection in CO₂ electrolysis based on Ni-YSZ electrode SOEC.

The amorphous hydrogenated (a-C:H) film-coated titanium, using different CH₄/H₂ and deposition times, was prepared by the ion beam deposition (IBD) method, which has the advantage of high adhesion because of the graded interface mixes at the atomic level. The chemical characterizations and corrosion behaviors of a-C:H film were investigated and evaluated by SEM, AFM, Raman spectroscopy, EPMA, TEM and XPS. An a-C:H film-coated titanium was corroded at 0.8 V, 90 °C in a 0.5 mol/L H₂SO₄ solution for 168 h. The metal ion concentration in the H₂SO₄ corrosion solution and the potentiodynamic polarization behavior were evaluated. Results indicate that a higher CH₄/H₂ of 1:0 and a deposition time of 12 h can result in a minimum I_D/I_G ratio of 0.827, Ra of 5.76 nm, metal ion concentration of 0.34 ppm in the corrosion solution and a corrosion current of 0.23 µA/cm². The current density in this work meets the DOE’s 2020 target of 1 µA/cm². Electrical conductivity is inversely proportional to the corrosion resistance. The significant improvement in the corrosion resistance of the a-C:H film was mainly attributed to the increased sp³ element and nanocrystalline TiC phase in the penetration layer. As a result, the a-C:H film-coated titanium at CH₄/H₂ = 1:0 with improved anti-corrosion behavior creates a great potential for PEMFC bipolar plates.