Multifunctional asymmetric electrolyte membrane encouraging durable lithium-metal batteries in wide temperature variations

The progress of high-performance lithium-metal batteries (LMBs) has been greatly impeded by lithium dendrite growth and electrolyte performance defects. Herein, an ultra-thin asymmetric multilayer composite electrolyte with a total thickness of 19 μm is designed. The rigid metal-organic framework (MOF) tier with Li+ conductivity towards the anode side adjusts the even deposition of Li+, owns high elasticity modulus (6.4 GPa) to restrain lithium dendrite formation, and improves the thermostability of the membrane. The in-situ cross-linked polymer layer on the cathode side achieves good electrode-electrolyte interface contact. Consequently, the functional asymmetric multilayer composite electrolyte displays a superior ionic conductivity (0.68 mS cm−1) and a high-efficiency Li+ transference (tLi+ = 0.47). The assembled Li||Li symmetric cells can cycle steadily for 1500 h at a high current density of 3 mA cm−2 at 30 °C and 1000 h at 1 mA cm−2 at 100 °C. The assembled LMBs with different cathodes show high rate capability and long-period cycling stability at room temperature. More impressively, the batteries display excellent electrochemical performance within −15 °C-100 °C and do not cause a short circuit even at 170 °C, showing high thermal safety. This work frames a neoteric strategy for the practical application of LMBs.