Surface Defects Reinforced Polymer‐Ceramic Interfacial Anchoring for High‐Rate Flexible Solid‐State Batteries

Abstract

High Li + conductivity, good interfacial compatibility and high mechanical strength are desirable for practical utilization of all-solid-state electrolytes. In this study, by introducing Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) with surface defects into poly(ethylene oxide) (PEO), a composite solid electrolyte (OV-LLZTO/ PEO) is prepared. The surface defects serve as anchoring points for oxygen atoms of PEO chains, forming a firmly bonded polymer-ceramic interface. This bonding effect effectively prevents the agglomeration of LLZTO particles and crystallization of PEO domains, forming a homogeneous electrolyte membrane exhibiting high mechanical strength, reduced interfacial resistance with electrodes as well as improved Li + conductivity. Owing to these favorable properties, OV-LLZTO/PEO can be operated under a high current density (0.7 mA cm −2 ) in a Li-Li symmetric cell without short circuit. Above all, solidstate full-cells employing OV-LLZTO/PEO deliver state-of-the-art rate capability (8 C), power density and capacity retention. As a final proof of concept study, flexible pouch cells are assembled and tested, exhibiting high cycle stability under 5 C and excellent safety feature under abusive working conditions. Through manipulating the interfacial interactions between polymer and inorganic electrolytes, this study points out a new direction to optimizing the performance of all-solid-state batteries.

Ammonium fluoride induced barrier-free and oxygen vacancy enhanced LLZO powder for fast interfacial lithium-ion transport in composite solid electrolytes

“…The results indicate the reduction of Zr and oxidation of La at the surface of LLZO powder, which conrms the formation of oxygen vacancies. 37 To the best of our knowledge, this is the rst time that oxygen vacancies in LLZO formed at lower than 400 °C.…”

“…Oxygen vacancies can be created through thermal treatment under a reductive atmosphere, 36 which provide firm contact between the LLZO surface and oxygen-containing polymer segments. 37 Consequently, improved Li + conductivity was achieved. The in situ formed LiF as an electrolyte additive was equally distributed in the polymer matrix during the manufacturing process, which extended the stable electrochemical window of CPE.…”

Ionic Conductivity and Cycling Performance in PEO Polymer Electrolyte Enhanced by Non-Milled In Situ Nano-LLZO Powders

“…Thus, it can form a uniform electrolyte film. 35 Besides, numerous studies have investigated the ionic conductivities of LLZO−PEO composites at different LLZO concentrations and plotting the data to observe variation trend in conductivities of LLZO−PEO composite electrolytes. As a result, the ionic conductivity of 7.5% LLZO−PEO electrolyte is proved to be the highest value.…”

“…This combination can effectively prevent the agglomeration of LLZO fillers and the crystallization of PEO. Thus, it can form a uniform electrolyte film . Besides, numerous studies have investigated the ionic conductivities of LLZO–PEO composites at different LLZO concentrations and plotting the data to observe variation trend in conductivities of LLZO–PEO composite electrolytes.…”

Stable Li|LAGP Interface Enabled by Confining Solvate Ionic Liquid in a Hyperbranched Polyanionic Copolymer for NASICON-Based Solid-State Batteries

“…Traditional commercial lithium-ion batteries usually use toxic, flammable, and corrosive liquid (organic) electrolytes, thereby bringing potential safety hazards, such as battery explosion and short circuits caused by thermal runaway behavior and uncontrolled growth of lithium dendrites. − Therefore, safety is one of the most critical issues to be solved in developing large-scale applications for secondary lithium batteries with long cycling life. − Compared with the organic liquid electrolytes, ceramic electrolytes, such as NASICON, perovskites, garnet, and sulfide-type ceramic/glass, have the advantages of non-flammability, a high shear modulus (10–100 GPa) against Li dendrite growth, and a high Li-ion transference number ( t Li+ ≈ 1) at room temperature (R.T.). − Thus, all-solid-state lithium–metal batteries are recognized as the best candidate for next-generation energy storage by replacing the liquid electrolyte with a solid electrolyte (SE). − Unfortunately, these SEs suffer from physicochemical stability issues, including high impedance at solid/solid interfaces and poor chemical stability in contact with Li metal, which hinder the application of solid-state batteries.…”