Ultra-stable Li||LiFePO batteries via advanced designing of localized high concentration electrolyte.

The High-Performance Li-LiFePO batteries (Li||LFP) realized by highly compatible electrolytes are considered to be the breakthrough point to achieve the stability and high energy density of lithium-ion battery (LIB) systems. However, the current prevailing commercial electrolytes can hardly be compatible with both LFP cathode and lithium anode simultaneously to an ideal extent. On this very note, we designed an advanced ether-based localized high concentration electrolyte (abbreviated as "ADE"), which exhibits extreme compatibility with LFP-based lithium metal batteries (Fb-LMBs). Equipped with ADE-electrolyte, the Li||LFP coin cell system can carry out more than 4000 fast-charging/discharging (3C for charge and 6C for discharge, respectively) rigorously cycles. Each cycle can not only sacrifice just 0.145‱ capacity on average compared with the original value, but also cycle at elevated temp (>200 fast charging/discharging cycles under 60 °C). This performance remains rare in liquid electrolyte systems in previous reports. The significantly enhanced electrochemical performance can be ascribed to the stabilization of both LFP-cathode/electrolyte and Li-metal-anode/electrolyte interphases. In addition, due to its specific solvated sheath structure, its wettability and flame-retarding properties are superior to those of the control group. This work expands the space for designing a stable fast-charge LFP-based system and sheds light on the possibility of replacing the most popular graphite||LFP system with Li ||LFP configuration with high energy density and stable cyclic performance.