Confining nonflammable liquid in solid polymer electrolyte to enable nickel-rich cathode-based 4.2 V high-energy solid-state lithium-metal and lithium-ion batteries

Solid polymer electrolyte (SPE)-based solid-state batteries (SSBs) offer a potential safety, but the integration of practical cathode loading for high-energy density SSBs is a challenge. Herein, we demonstrate a proof of unique design concept of NonFlammable Liquid-confined in-Solid Polymer Electrolyte (NFL-SPE) enabling highly loaded (10 mg cm(-2)) LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode-based 1.5 mAh cm(-2) class solid-state 4.2 V Li-metal and Li-ion batteries. in-situ crosslinked semi-interpenetrating polymer network SPE maintains its solid form when limiting the confined NFL amount to 35 wt%. The NFL comprises propylene carbonate, fluorinated linear carbonates, and solid electrolyte interphase-forming additives of lithium bis(phthalate)borate and vinylene carbonate. The critical roles of NFL are to enhance ion conductivity to 2-fold from SPE only and 1000-fold from traditional poly(ethylene) oxide, to permit a facile interfacial wetting to highly loaded NCM811 and to reduce interfacial resistance. A higher discharge capacity of 169 mAh g(-1) is achieved with Li/NFL-SPE/NCM811 at 45 degrees C with improved cycling performance and a suppressed lattice contraction of NCM811 along the c-axis, compared to that with SPE only. Importantly, an unprecedented 1.5 mAh cm(-2)-class solid-state Li-ion battery is realized by fabricating silicon-graphite/NFL-SPE/NCM811 utilizing silicon (5 wt%)-graphite anode active material and showing stable 50 cycles at 25 degrees C. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

In this study, a unique design concept of confining nonflammable liquid in solid polymer electrolyte was demonstrated, enabling high cathode loading in solid-state batteries. The nonflammable liquid enhanced ion conductivity, improved interfacial wetting, and reduced interfacial resistance, resulting in higher discharge capacity and cycling performance.