Solid-state lithium batteries using inorganic electrolytes are expected to revolutionize energy storage systems due to their better safety and high energy density. However, their application is greatly hindered by the poor solid-solid interface between the solid-state electrolyte (SSE) and electrodes, particularly the cathode. Herein, we report a facile strategy to address the high cathode/SSE interfacial resistance through rapid, high-temperature microwave soldering. As a proof-of-concept demonstration, we soldered a garnet-type Li₇La₃Zr₂O₁₂ (LLZO) SSE with a V₂O₅ cathode, which feature high thermal stability and suitable melting temperatures. Our microwave soldering technique can selectively melt the surface of the granular V₂O₅ and rapidly form an intact and continuous cathode layer with tightly embedded carbon black nanoparticles, leading to a remarkable 690-time increase of the electronic conductivity of cathode. Additionally, the melted V₂O₅ cathode is conformally soldered to the garnet electrolyte, resulting in a 28-fold decrease of the cathode/garnet interfacial resistance (from 14.4 ​kΩ ​cm²to 0.5 ​kΩ ​cm². As a result, this all-solid-state full cell displays a low overall resistance of 0.3 ​kΩ ​cm² at 100 ​°C, which enables stable cyclability of the battery without the addition of liquid/polymer electrolyte. The fast microwave soldering strategy constitutes a significant step towards the development of the all-solid-state batteries.

由于使用无机电解质的固态锂电池具有更高的安全性和较高的能量密度，因此有望彻底改变储能系统。但是，由于固态电解质（SSE）与电极（尤其是阴极）之间不良的固-固界面，极大地阻碍了它们的应用。本文中，我们报告了一种通过快速高温微波焊接来解决高阴极/ SSE界面电阻的简便策略。作为概念验证的演示，我们将石榴石型Li ₇ La ₃ Zr ₂ O ₁₂（LLZO）SSE与V ₂ O ₅焊接在一起。阴极，具有很高的热稳定性和合适的熔化温度。我们的微波焊接技术可以选择性地熔化V ₂ O ₅颗粒的表面，并通过紧密嵌入的炭黑纳米颗粒快速形成完整连续的阴极层，从而使阴极的电子电导率显着提高690倍。此外，将熔化的V ₂ O ₅阴极保形焊接到石榴石电解质上，导致阴极/石榴石界面电阻降低了28倍（从14.4kΩcm ^2降低到0.5kΩcm ²。 ，这种全固态全电池显示出0.3kΩcm ²的低总电阻在100°C的温度下，无需添加液体/聚合物电解质即可实现电池的稳定循环性。快速微波焊接策略是向全固态电池发展迈出的重要一步。