A Low Temperature Soldered All Ceramic Lithium Battery

The oxide-based all ceramic lithium battery (ACLB) is regarded as one of the safest secondary batteries because it is incombustible and free of toxic gas release. However, high temperature sintering is a necessary step to fabricate the solid-state electrolytes (SSEs) membranes and improve the cathode/SSEs interfacial contact, which bring in high energy consumption as well as the formation of Li-ion resistive interdiffusion phases. Here, we report an in situ coating of lithium-rich antiperovskites (LiRAPs) as sintering aids to solder LiCoO₂ (LCO) active material and Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) solid electrolyte. Due to the low melting point of LiRAPs (273.2 °C), all particles were compactly soldered to simultaneously densify the electrolyte membrane and reinforce the cathode/electrolyte contact, thus lowing the sintering temperature of ACLB from over 600 °C to only 290 °C. The interfacial resistance of cathode/electrolyte was reduced from 15 288 to 817 Ω/cm² due to the high ionic conductivity of LiRAPs and the interdiffusion phases prohibition. Moreover, the outstanding ductility of LiRAPs also mitigated the strain/stress of the LCO/LATP interface, which lead to improved cycling stability. These results not only provide a rational design to the cathode/SSEs interface but also deliver a practical stacking process to speeding up the industrialization of ACLB.