A nanostructured cathode architecture for low charge overpotential in lithium-oxygen batteries

Abstract

The lithium-oxygen battery, of much interest because of its very high-energy density, presents many challenges, one of which is a high-charge overpotential that results in large inefficiencies. Here we report a cathode architecture based on nanoscale components that results in a dramatic reduction in charge overpotential to B0.2 V. The cathode utilizes atomic layer deposition of palladium nanoparticles on a carbon surface with an alumina coating for passivation of carbon defect sites. The low charge potential is enabled by the combination of palladium nanoparticles attached to the carbon cathode surface, a nanocrystalline form of lithium peroxide with grain boundaries, and the alumina coating preventing electrolyte decomposition on carbon. High-resolution transmission electron microscopy provides evidence for the nanocrystalline form of lithium peroxide. The new cathode material architecture provides the basis for future development of lithium-oxygen cathode materials that can be used to improve the efficiency and to extend cycle life.

Recent Development of Advanced Electrode Materials by Atomic Layer Deposition for Electrochemical Energy Storage

“…c,d) Reproduced with permission 70. e,f) Reproduced with permission 78. Copyright 2013, Nature Publishing Group.…”

“…As an unique surface modification process for electrodes of LIBs, ALD surface coating has been conducted with cathode materials of Li–O 2 battery 77. Utilizing ALD Al 2 O 3 and Pd, Lu et al developed a novel cathode material of palladium nanoparticles and thin alumina layer coated on carbon 78. As shown in Figure 5e–f, the ALD alumina layer effectively protects the carbon surface and prevents the decomposition of electrolytes, while the nanosized Pd electrocatalyst promotes the formation of nanocrystalline discharge product of Li 2 O 2 , which is beneficial for charge transport.…”

High‐Performance Li–O2 Batteries with Controlled Li2O2 Growth in Graphene/Au‐Nanoparticles/Au‐Nanosheets Sandwich

“…Peng et al found that Li–O 2 battery can retain 95% of its capacity after 100 cycles with a low‐charge overpotential by using a nanoporous gold cathode 28. Recent reports have shown that Li–O 2 batteries with noble metal catalysts, such as Pd,29, 30, 31 Ru,32, 33, 34, 35 and Pt,36, 37, 38, 39 exhibited low overpotentials and long‐term cycling stability. To prepare noble‐metal‐based catalysts, a carbon material is usually needed to support the noble metals.…”

“…Unfortunately, carbon materials suffer from decomposition in the presence of Li 2 O 2 or LiO 2 ,40, 41, 42 especially those with defects 43. In addition, carbon, particularly that contains defects, also catalyzes the electrolyte decomposition during cycling 30, 41. Furthermore, polymer binders are chemically/electrochemically unstable in contact with Li 2 O 2 or LiO 2 44, 45, 46…”

“…In this regard, a modification on carbon materials is required to minimize the detrimental effects. Lu et al provided a useful way to deactivate the active carbon defect sites through an alumina coating 30. The active sites on carbon could also be deactivated by in situ electrochemical nitrogen doping 58.…”