Layered LiCoO(2–)LiFeO(2) Heterostructure Composite for Semiconductor-Based Fuel Cells

Enabling fast ionic transport at a low-temperature range (400–600 °C) is of great importance to promoting the development of solid oxide fuel cells (SOFCs). In this study, a layer-structured LiCoO(2)–LiFeO(2) heterostructure composite is explored for the low-temperature (LT) SOFCs. Fuel cell devices with different configurations are fabricated to investigate the multifunction property of LiCoO(2)–LiFeO(2) heterostructure composites. The LiCoO(2)–LiFeO(2) composite is employed as a cathode in conventional SOFCs and as a semiconductor membrane layer in semiconductor-based fuel cells (SBFCs). Enhanced ionic conductivity is realized by a composite of LiCoO(2)–LiFeO(2) and Sm(3+) doped ceria (SDC) electrolyte in SBFC. All these designed fuel cell devices display high open-circuit voltages (OCVs), along with promising cell performance. An improved power density of 714 mW cm(−2) is achieved from the new SBFC device, compared to the conventional fuel cell configuration with LiCoO(2)–LiFeO(2) as the cathode (162 mW cm(−2) at 550 °C). These findings reveal promising multifunctional layered oxides for developing high-performance LT–SOFCs.