XPS investigations of electrolyte/electrode interactions for various Li-ion battery materials

Abstract

For future Li-ion battery applications the search for both new design concepts and materials is necessary. The electrodes of the batteries are always in contact with electrolytes, which are responsible for the transport of Li ions during the charging and discharging process. A broad range of materials is considered for both electrolytes and electrodes so that very different chemical interactions between them can occur, while good cycling behavior can only be obtained for stable solid-electrolyte interfaces. X-ray photoelectron spectroscopy (XPS) was used to study the most relevant interactions between various electrode materials in contact with different electrolyte solutions. It is shown how XPS can provide useful information on reactivities and thus preselect suitable electrode/electrolyte combinations, prior to electrochemical performance tests.

Graphene and Graphene‐Based Materials for Energy Storage Applications

“…As illustrated in Equation , the desired electrochemical reaction product for a rechargeable Li‐air battery should be Li 2 O 2 , which is the only desired product to enable the rechargeability of the Li‐oxygen battery. However, the intermediates during oxygen reduction, e.g., O 2 − , O 2 2− , LiO 2 /LiO 2 − are rather reactive and can easily decompose most organic electrolytes . Therefore, normally the discharge products of a Li‐air battery are mainly composed of various side products instead of Li 2 O 2 .…”

“…However, the intermediates during oxygen reduction, e.g., O 2 − , O 2 2− , LiO 2 /LiO 2 − are rather reactive and can easily decompose most organic electrolytes. [138][139][140] Therefore, normally the discharge products of a Li-air battery are mainly composed of various side products instead of Li 2 O 2 . For example, Li 2 CO 3 , lithium alkylcarbonates, and LiOH are the main products when using carbonates as electrolytes.…”

Recent Advances in Non‐Aqueous Electrolyte for Rechargeable Li–O2 Batteries

“…The commercially used lithium hexafluorophosphate (LiPF 6 ) in Li‐ion batteries, was found to react with Li 2 O 2 through X‐ray photoelectron spectroscopy (XPS) result . Also, a series of Li salts (LiBF 4 , LiPF 6 , LiClO 4 , and LiTFSA) were tested in Li–O 2 batteries with the help of XPS.…”

Chemical reactivity of aprotic electrolytes on a solid Li2O2 surface: screening solvents for Li–air batteries

“…Surprisingly, the chemical reactivity of Li 2 O 2 , which is the desired discharge product, was ignored in the early development of Li-air cells, and only recently was its crucial importance highlighted in both theoretical [12] and experimental studies [16][17][18][19]. In a recent paper of ours [12], the problem of whether the peroxide, O 2− 2 , can be considered a pivotal discharge product for the decomposition of carbonate-based electrolytes was addressed by using large scale simulations to model the reactivity of a surface of Li 2 O 2 in contact with liquid PC (electrolyte thickness approximate 2 nm and a total system size of approximate 1000 atoms), with ab initio molecular dynamics techniques.…”