Abstract
Multilayer ceramic lithium batteries (MLCBs) are regarded as a new type of oxide-based all-solid-state microbattery for integrated circuits and various wearable devices. The chemical compatibility between the solid electrolyte and electrode active materials during the high-temperature co-sintering process is crucial for determining the structural stability and cycling performance of MLCBs. This study focuses on the typical MLCB composite electrodes composed of the NASICON-type Li(1.3)Al(0.3)Ti(1.7)(PO(4))(3) (LATP) solid electrolyte and the spinel-type Li(4)Ti(5)O(12) (LTO) anode material. The thermal behavior, phase structure, morphological evolution, and elemental chemical states of these composite electrodes were systematically investigated over a co-sintering temperature range of 400-900 °C. The results indicate that the reactivity between LATP and LTO during co-sintering is primarily driven by the diffusion of Li from the LTO anode, leading to the formation of TiO(2), Li(3)PO(4), and LiTiOPO(4). Furthermore, the co-sintered LATP-LTO multilayer composites reveal that the generation of Li(3)PO(4) at the LATP/LTO interface facilitates their co-sintering integration at 800-900 °C, which is essential for the successful fabrication of MLCBs. These findings provide direct evidence and valuable references for the structural and performance optimization of MLCBs in the future.