Utilizing the Intrinsic Thermal Instability of Swedenborgite Structured YBaCoO as an Opportunity for Material Engineering in Lithium-Ion Batteries by Er and Ga Co-Doping Processes.

We firstly introduce Er and Ga co-doped swedenborgite-structured YBaCoO (YBC) as a cathode-active material in lithium-ion batteries (LIBs), aiming at converting the phase instability of YBC at high temperatures into a strategic way of enhancing the structural stability of layered cathode-active materials. Our recent publication reported that YErBaCoGaO (YEBCG) showed excellent phase stability compared to YBC in a fuel cell operating condition. By contrast, the feasibility of the LiCoO (LCO) phase, which is derived from swedenborgite-structured YBC-based materials, as a LIB cathode-active material is investigated and the effects of co-doping with the Er and Ga ions on the structural and electrochemical properties of Li-intercalated YBC are systemically studied.