Electronic properties of lithium-ion battery cathodes studied in ion-gated transistor configuration

Electronic and ionic transport governs lithium-ion battery (LIB) operation. The in operando study of electronic transport in lithium-ion transition metal oxide (LMOx) cathodes at different states of charge enables the evaluation of the state of health of LIBs and the optimization of their performance. We report on electronic transport in LIB cathode materials at different states of charge controlled in operando in ion-gated transistor (IGT) configuration. We considered LiNi0.5Mn0.3Co0.2O2 (NMC532)- and LiMn1.5Ni0.5O4 (LNMO)-based composite materials formulated like in conventional LIB cathodes and operated in the organic electrolyte LP30 (1M LiPF6 in ethylene carbonate:dimethyl carbonate 1:1 v/v). NMC532- and LNMO-based cathode materials were used as the transistor channel materials and LP30 as the ion gating medium. Beyond its impact on the field of LIBs, our work advances the design of novel devices based on mixed ionic and electronic transport, including neuromorphic computing. [Display omitted] •The electronic conductivity of Lithium-ion battery electrodes is detected operando•Lithium-ion battery cathodes are used as ion-gated transistor channel materials•The electronic conductivity of the cathodes increases with their delithiation•Ion-gated transistors enable evaluation of the lithium-ion battery state of health Electrochemistry; Applied sciences; Energy storage