Hybrid Electrolytes with Controlled Network Structures for Lithium Metal Batteries

Overview

Solid polymer electrolytes (SPEs) with high conductivity and excellent resistance to lithium dendrite growth are highly desirable for the safe operation of lithium batteries. We herein report the facile one-pot synthesis of nanoparticle-containing cross-linked SPEs based on polyhedral oligomeric silsesquioxanes (POSS) and poly(ethylene glycol) (PEG). Conductivity, mechanical properties, and resistance to dendrite growth of the electrolytes can be tuned by controlling the network structures. Our hybrid SPEs exhibit superior dendrite inhibition even at high current densities. The all-solid-state lithium metal batteries fabricated using our SPEs show excellent cycling stability and rate capability. This hybrid material could significantly improve the performance and safety of lithium batteries.

Applications

Lithium metal batteries
Lithium ion batteries
Energy storage
Energy harvesting

Advantages

Superior lithium dendrite inhibition
Stable at high current densities
Excellent cycling stability
Excellent rate capability
Easy to process

Intellectual Property and Development Status

PCT Patent Pending- PCT/US2016/045830

References

Pan, Q. W.; Smith, D. M.; Qi, H.; Wang, S. J.; Li, C. Y. Hybrid Electrolytes with Controlled Network Structures for Lithium Metal Batteries. 2015, 27, 5995–6001.

Configuration of the lithium symmetric cell. Galvanostatic cycling curves of the cells with POSS-4PEG2K as separators at current densities of 0.3 mA/cm2 (b), 0.5 mA/cm2 (c), and 1.0 mA/cm2 (d). (e) Charge passed the lithium symmetric cell (Cd) in the galvanostatic cycling tests at different current densities. The measurements were conducted at 90 C. Note that the cell was still stable after 2600 hours cycling (Cd > 2808 C/cm2) at J = 0.3 mA/cm2 for POSS-4PEG2K.

The geometry of the Li/LiFePO4 full battery with POSS-2PEG6K as the electrolyte. (b) Charge and discharge profiles of the batteries at different rates. (c) Voltage vs. time profile for 41-50 galvanostatic cycles of the LMB at a C/2 rate. (d) Capacity and columbic efficiency vs. cycle number of the LMBs during galvanostatic cycling at C/2 and C/3 rates. The measurements were conducted at 90 C.