Stabilizing oxide interfaces against liquid organic electrolytes is critically important for effective reversible long-term cycling of cathodes in lithium-ion batteries (LIBs). For example, the discovery of passivation of graphite electrode using reductive decomposition of ethylene carbonate molecules from the electrolyte to form SEI certainly has aided in the commercialization of LIBs. The formation of stable, ionically-conducting and passivating interface at the cathode is also critically important if the LIB is charged to higher and higher voltages to up energy densities. Many papers describe cubic spinel LiMn2O4 (LMO) and its slightly Li-rich Li1.04Mn0.96O4 cousin, or doped versions to aid in its stability and cyclability. However, lithium manganese spinel oxides still suffer from complex manganese dissolution phenomena at the interfaces. While many characterization methods abound in the study of oxides, most of them interrogate just the bulk structure via penetrating neutrons or X-rays. Indeed there are techniques to implement specifically for surface measurements, for example soft X-rays, and electron spectroscopies. In a different approach, we have used the application of light to both measure the behavior and potentially control the interfacial electrochemistry through photochemical reactions has been implemented. In the present work, we designed an open coin-cell as a straight-forward test vehicle for applying broadband UV/Vis light to interrogate, change, and potentially control the LMO interface under operando electrochemical conditions. In this presentation we will describe these light-driven optical experiments and share the findings.

Renaissance of LiMn2O4 spinel

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.