Nanoconfined growth of lithium-peroxide inside electrode pores: A noncatalytic strategy toward mitigating capacity-rechargeability trade-off in lithium-air batteries

Abstract

Capacity-rechargeability trade-off in lithium-air batteries remains as one of the major challenges before their practical realization. As the discharge capacity increases, an uncontrolled growth of lithium-peroxide leads to passivation of the conductive electrode by a thick insulating layer that limits charge transport and results in a high overpotential during recharge. In contrast, deposition of lithium-peroxide inside a spatially confined electrode-space can restrict the growth and improve the rechargeability of the cell. The small crystallite size of spatially confined lithium-peroxide inside a porous framework is expected to show higher charge-transport that should play a crucial role in its facile decomposition. Here, a prototypical approach shows how a controlled increase in pore diameter, pore volume and electrochemically active surface area of a mesoporous carbon produces much higher discharge capacity by improving mass diffusion inside the mesoporous channels, yet simultaneously achieves an efficient rechargeability due to pore-confinement of lithium-peroxide.