Lipoic Acid-Assisted In Situ Integration of Ultrathin Solid-State Electrolytes

Ultrathin solid-state electrolytes (SSEs) have contributed to high-energy-density lithium-ion batteries (LIBs). However, when reducing thickness of SSEs, mechanical properties will inevitably deteriorate, even increasing the safety hazards. In this work, we developed an in-situ integration strategy to form an ultrathin SSE by combining a lipoic acid-assisted semi-interpenetrating polymer network and an ultrathin porous membrane. With this strategy, the thickness of the obtained SSE (named LA-SSE) is only 10 mu m, and the LA-SSE possesses extraordinary mechanical performances to suppress the growth of lithium dendrites. Meanwhile, the flexible LA-SSE presents anionic conductivity of 0.036 mS cm-1 and promotes interfacial compatibility between the lithium anode and the electrolyte. By employing LA-SSE as the electrolyte, the assembled Li parallel to LA-SSE parallel to Li symmetric cell operated with long-term cycling (more than 3000 h), and the LiFePO4 parallel to LA-SSE parallel to Li full battery worked steadily over 200 cycles at 0.5 C with a capacity retention of 84% at room temperature. This work provides a promising strategy for designing ultrathin SSEs, with satisfactory mechanical properties, excellent interfacial compatibility, and safety, for LIBs.

Automated summary

In this work, an ultrathin solid-state electrolyte (SSE) named LA-SSE was developed by combining a lipoic acid-assisted semi-interpenetrating polymer network and an ultrathin porous membrane. LA-SSE, with a thickness of only 10 μm, showed excellent mechanical properties to suppress lithium dendrite growth and favorable interfacial compatibility between the lithium anode and electrolyte. By using LA-SSE as the electrolyte, long-term cycling of over 3000 hours was achieved in a Li parallel to LA-SSE parallel to Li symmetric cell, and a LiFePO4 parallel to LA-SSE parallel to Li full battery exhibited stable operation over 200 cycles with a capacity retention of 84% at room temperature. This study provides a promising strategy for designing ultrathin SSEs with satisfactory mechanical properties, excellent interfacial compatibility, and safety for lithium-ion batteries.