Reduced Graphene Oxide and Pd Nanocomposite as a Catalyst for Oxygen Reduction Reaction in Rechargeable Li‐Oxygen Battery

다국어 초록 (Multilingual Abstract)

Pd+2 ions are reduced on two‐dimensional reduced graphene oxide nanosheets in aqueous phase by NaBH4 as reducing agent. Pd nanoparticles are uniformly grown on graphene sheets in 5–15 nm range, verified by TEM investigation. Oxygen reduction reaction (ORR) is carried in nonaqueous medium by using rotating disk electrode technique. For comparison, ORR activity of pure RGO is also studied; ORR follows one e− pathway (O2 + e−=O2−) in non‐aqueous electrolyte. Pd‐RGO has ORR activity five times more as compared to pure RGO in 0.10 M TBAP‐DMSO solution. Pd‐RGO catalyst is used to assemble the non‐aqueous Li‐O2 batteries and charge‐discharge cycling is carried out. At 0.20 mA cm−2 the discharge capacity of 8192 mAh g−1 is obtained. Overpotential for ORR (or discharge) step is 260 mV. This is first report on reaction chemistry in Li‐O2 battery using Pd nanoparticles. Li2O2 and Li2O are confirmed as discharged products by ex‐situ XRD studies.
Pd nanoparticles are decorated by in‐situ chemical method on graphene nanosheets for O2 reduction reaction for non‐aqueous Li‐O2 battery. ORR follows one e− pathway (O2 + e−=O2−) on Pd nanoparticles in DMSO electrolyte. The overpotential for discharge process was 260 mV at 0.20 mA cm−2 current density. Discharge capacity was 8192 mAh g−1 at low current. This is first report for investigating discharge products (Li2O and Li2O2) of Li‐O2 battery with Pd nanoparticles in DMSO.