MXene Electrodes\nfor All Strain-Free Solid-State Batteries

All-solid-state batteries with nonflammable inorganic\nsolid electrolytes\nare the key to addressing the safety issues of lithium-ion batteries\nwith flammable organic liquid electrolytes. However, conventional\nelectrode materials suffer from substantial volume changes during\nLi<sup>+</sup> (de)intercalation, leading to mechanical failure of\ninterfaces between electrode materials and solid electrolytes and\nthen severe performance degradation. In this study, we report strain-free\ncharge storage via the interfaces between transition metal carbides\n(MXenes) and solid electrolytes, where MXene shows negligible structural\nchanges during Li<sup>+</sup> (de)intercalation. <i>Operando</i> scanning electron transmission microscopy with electron energy-loss\nspectroscopy reveals the pillar effect of trapped Li<sup>+</sup> in\nthe interlayer spaces of MXene to achieve the strain-free features.\nAn all strain-free solid-state battery, which consists of a strain-free\nTi<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> negative\nelectrode and a strain-free disordered rocksalt Li<sub>8/7</sub>Ti<sub>2/7</sub>V<sub>4/7</sub>O<sub>2</sub> positive electrode, demonstrates\nlong-term stable operation while preserving the interfacial contact\nbetween electrode materials and solid electrolytes.