High‐Performance Solid Polymer Electrolytes Filled with Vertically Aligned 2D Materials

Abstract

Solid state lithium metal batteries are the most promising next-generation power sources owing to their high energy density and safety. Solid polymer electrolytes (SPE) have gained wide attention due to the excellent flexibility, manufacturability, lightweight, and low-cost processing. However, fatal drawbacks of the SPE such as the insufficient ionic conductivity and Li + transference number at room temperature restrict their practical application. Here vertically aligned 2D sheets are demonstrated as an advanced filler for SPE with enhanced ionic conductivity, Li + transference number, mechanical modulus, and electrochemical stability, using vermiculite nanosheets as an example. The vertically aligned vermiculite sheets (VAVS), prepared by the temperature gradient freezing, provide aligned, continuous, run-through polymer-filler interfaces after infiltrating with polyethylene oxide (PEO)-based SPE. As a result, ionic conductivity as high as 1.89 × 10 −4 S cm −1 at 25 °C is achieved with Li + transference number close to 0.5. Along with their enhanced mechanical strength, Li|Li symmetric cells using VAVS-CSPE are stable over 1300 h with a low overpotential. LiFePO 4 in all-solid-state lithium metal batteries with VAVS-CSPE could deliver a specific capacity of 167 mAh g −1 at 0.1 C at 35 °C and 82% capacity retention after 200 cycles at 0.5 C.

MXene‐Based Mesoporous Nanosheets Toward Superior Lithium Ion Conductors

“…As shown in Figure S16a,b, Supporting Information, both the LiTFSI contents and MXene‐mSiO 2 levels have large influences on the ionic conductivities. The highest value of 4.6 × 10 −4 S cm −1 is achieved as the content of LiTFSI is 30 wt% and the level of MXene‐mSiO 2 is 2 wt%, which is twice than that of the reported silica particle/ePPO electrolyte (2.3 × 10 −4 S cm −1 ) and five orders of magnitude higher than that of the reported MXene/PEO electrolyte (7 × 10 −10 S cm −1 ) and other solid polymer electrolytes (10 −10 –10 −4 S cm −1 , Table S1, Supporting Information) . To the best of our knowledge, this is the highest ionic conductivity for all solid polymer electrolytes.…”

Eliminating Dendrites through Dynamically Engineering the Forces Applied during Li Deposition for Stable Lithium Metal Anodes

“…[5,14] 3) The uncontrollable Li dendrite growth impales the separator, resulting in catastrophic combustion and explosion. [24][25][26][27] Specifically, structured anode can manipulate the electric field redistribution on Li surface, decrease the local current density and accommodate large volume fluctuation during cycling, while the unwell protected large surface area would lead to more serious parasite reactions. [24][25][26][27] Specifically, structured anode can manipulate the electric field redistribution on Li surface, decrease the local current density and accommodate large volume fluctuation during cycling, while the unwell protected large surface area would lead to more serious parasite reactions.…”

A Compact Gel Membrane Based on a Blend of PEO and PVDF for Dendrite‐Free Lithium Metal Anodes

“…The higher uptake to liquid electrolyte (92.3 wt.%) makes Celgard 2730 show higher ionic conductivity. In addition, the ionic conductivity of achieved GM is also higher than that of novel PEO‐based solid PEs with two‐dimension materials as additives due to the gelation by LiPF 6 ‐based liquid electrolyte …”