TY - JOUR

T1 - The role of transition metal interfaces on the electronic transport in lithium–air batteries

A1 - Chen,Jingzhe

A1 - Hummelshøj,Jens S.

A1 - Thygesen,Kristian Sommer

A1 - Mýrdal,Jón Steinar Garðarsson

A1 - Nørskov,Jens Kehlet

A1 - Vegge,Tejs

AU - Chen,Jingzhe

AU - Hummelshøj,Jens S.

AU - Thygesen,Kristian Sommer

AU - Mýrdal,Jón Steinar Garðarsson

AU - Nørskov,Jens Kehlet

AU - Vegge,Tejs

PB - Elsevier BV

PY - 2011

Y1 - 2011

N2 - Low electronic conduction is expected to be a main limiting factor in the performance of reversible lithium–air, Li–O2, batteries. Here, we apply density functional theory and non-equilibrium Green's function calculations to determine the electronic transport through lithium peroxide, Li2O2, formed at the cathode during battery discharge. We find the transport to depend on the orientation and lattice matching of the insulator–metal interface in the presence of Au and Pt catalysts. Bulk lithium vacancies are found to be available and mobile under battery charging conditions, and found to pin the Fermi level at the top of the anti bonding peroxide π*(2px) and π*(2py) levels in the Li2O2 valence band. Under an applied bias, this can result in a reduced transmission, since the anti bonding σ*(2pz) level in the Li2O2 conduction band is found to couple strongly to the metal substrate and create localized interface states with poor coupling to the Li2O2 bulk states. These observations provide a possible explanation for the higher overpotential observed for charging than discharge.

AB - Low electronic conduction is expected to be a main limiting factor in the performance of reversible lithium–air, Li–O2, batteries. Here, we apply density functional theory and non-equilibrium Green's function calculations to determine the electronic transport through lithium peroxide, Li2O2, formed at the cathode during battery discharge. We find the transport to depend on the orientation and lattice matching of the insulator–metal interface in the presence of Au and Pt catalysts. Bulk lithium vacancies are found to be available and mobile under battery charging conditions, and found to pin the Fermi level at the top of the anti bonding peroxide π*(2px) and π*(2py) levels in the Li2O2 valence band. Under an applied bias, this can result in a reduced transmission, since the anti bonding σ*(2pz) level in the Li2O2 conduction band is found to couple strongly to the metal substrate and create localized interface states with poor coupling to the Li2O2 bulk states. These observations provide a possible explanation for the higher overpotential observed for charging than discharge.

KW - Batteries and carbon-free chemical energy storage

KW - Batterier og kulstoffri kemisk energilagring

U2 - 10.1016/j.cattod.2010.12.022

DO - 10.1016/j.cattod.2010.12.022

JO - Catalysis Today

JF - Catalysis Today

SN - 0920-5861

IS - 1

VL - 165

SP - 2

EP - 9

ER -