Improving Li$_2$O$_2$ conductance via polaron preemption: an \textit{ab initio} study of Si doping

TL;DR

This study uses  initio simulations to show that silicon doping in Li O O  enhances electronic conductance by creating impurity states that prevent polaron formation, potentially improving battery performance.

Contribution

It introduces a novel doping strategy with silicon to preempt polaron formation, increasing conductivity in Li O O  for better battery applications.

Findings

Silicon doping creates stable impurity states in Li O O 's band gap.

These impurity states originate from antibonding orbitals of oxygen pairs.

Polaron formation is suppressed, leading to higher electronic mobility.

Abstract

We report on \textit{ab initio} electronic structure simulations of Li$_2$O$_2$, where 1.6% of lithium atoms are substituted by silicon. It is demonstrated that this leads to the formation of conducting impurity states in the band gap of Li$_2$O$_2$. We show that these states originate from the antibonding orbitals of the oxygen pairs and are remarkably stable against possible polaron formation (upon electron injection). Through this polaron preemption mechanism, the proposed compound is expected to show significantly higher electronic mobility than stoichiometric Li$_2$O$_2$, which could have significant applications in lithium-air batteries.