Shihua Li

Silver nanoparticles supported on a nitrogen-doped graphene aerogel composite catalyst for an oxygen reduction reaction in aluminum air batteries

Herein, we developed silver nanoparticles supported on a nitrogen doped graphene (Ag/N-RGO) aerogel by a facile one-step hydrothermal method as an efficient ORR electrocatalyst. The Ag/N-RGO showed remarkable catalytic activity and stability in the alkaline electrolyte. The as-proposed facile strategy to synthesize Ag/N-RGO is promising for the development of inexpensive ORR electrocatalysts.

La1−xAgxMnO3 electrocatalyst with high catalytic activity for oxygen reduction reaction in aluminium air batteries

The LaMnO3 (LMO) perovskite catalyst has been proposed as one of the best oxygen reduction reaction catalysts (ORRCs) to substitute noble metals. However, its ORR catalytic activity needs to be further improved. Here, La1−xAgxMnO3 (LAM) perovskites doped with Ag are synthesized by a facile improved sol–gel method. The structures, morphologies and valence states of Mn and oxygen adsorption behaviors of these LAM samples are characterized, and their catalytic activities toward ORR are studied by the rotating ring-disk electrode (RRDE) and aluminum air battery technologies. The results demonstrate that the doping of 30% Ag in the A-site of LMO (LAM-30) can effectively improve its ORR catalytic activity due to the regulation of the manganese valence and improvement of the oxygen adsorption capacity. Besides the remarkable ORR catalytic activity, the LAM-30 catalyst exhibits good durability. The current retention is as high as 98% after the aging test for 10 000 seconds. In addition, the maximum power density of the aluminum air battery using LAM-30 as the ORRC can reach 230.2 mW cm−2, which indicates that LAM-30 can be used as a promising ORRC in aluminum air batteries.

Promoting effects of Ce0.75Zr0.25O2 on the La0.7Sr0.3MnO3 electrocatalyst for the oxygen reduction reaction in metal–air batteries

Perovskites have been proposed as one of the best oxygen reduction reaction catalysts (ORRCs) to substitute noble metals though their catalytic activity still need to be improved. It is well accepted that improving the oxygen adsorption capacity is beneficial to the catalytic activity of La1−xSrxMnO3 (LSM) perovskites. Herein, we synthesized the LSM-based composite by compositing La0.7Sr0.3MnO3 with Ce0.75Zr0.25O2 (CZ) which is used as an excellent oxygen storage material by a two-step solution method. The LSM–CZ composite is revealed as a novel electrocatalyst for the oxygen reduction reaction with the direct four-electron transfer mechanism and a positive onset potential in comparison with the commercial Pt/C catalyst. And its onset potential is almost the most positive one among those of the perovskites stemmed from LaMnO3. In addition, the stability of LSM–CZ is even superior to that of Pt/C, and LSM–CZ almost accumulates no intermediate product of HO2− (∼0.8%) after aging for 100 000 seconds. By using LSM–CZ as the ORRC, the maximum power density of the aluminum–air battery can reach 233.4 mW cm−2. Our work paves the way for the development of perovskite catalysts for energy conversion and storage.

Performances of an Al–0.15 Bi–0.15 Pb–0.035 Ga alloy as an anode for Al–air batteries in neutral and alkaline electrolytes

Aluminum is a very good candidate anode for metal–air batteries due to its negative electrode potential, high theoretical electrochemical equivalent value, abundant reserves and environmental friendliness. The corrosion behavior and electrochemical properties of the Al–1.5Bi–1.5Pb–0.035Ga alloy were investigated by self-corrosion tests and electrochemical techniques, and compared with that of pure Al and Al–Bi–Pb alloys. The performances of Al–air batteries based on these alloy anodes were studied by constant current discharge and I–V discharge tests. The corrosion morphology and discharge surface were also investigated by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. The results show that the Al–Bi–Pb–Ga alloy provides a more negative potential and exhibits an enhanced activity in NaCl solution compared with pure Al and Al–Bi–Pb alloys, and gives high power density (253.4 ± 2.5 mW cm−2) and desirable anode efficiency (85.4 ± 0.5%) when used as an anode for Al–air batteries in KOH solution. Moreover, the dissolution mechanism of the Al–Bi–Pb–Ga alloy is also characterized based on the electrochemical measurements and microstructure observations.