A Multiscale Hollow Spherical LATP Active Filler Improves Conductivity and Mechanical Strength in Composite Solid Electrolytes for Li Batteries

Abstract

Polymer-based electrolytes would be ideal for all-solid-state Li metal batteries due to the superior processability of polymers and their ability to make good interfaces with electrode materials. However, polymer electrolytes have lower room temperature Li+ conductivities than desired. Composite solid electrolytes (CSEs) containing both polymer and ceramic filler have far greater conductivity than the polymer alone, and it is believed this is due to conduction paths along the polymer–ceramic interface. A strategy often pursued for increasing conductivity has been to engineer the filler with a high aspect ratio shape, such as nanorods or interconnected nanofibers. In this work we employ a multiscale hollow spherical filler, which is not directional but achieves similar conductivity to those with fibrous morphologies. The hollow spherical shape avoids agglomeration and provides continuous Li+ transfer channels. We fabricated multiscale hollow spherical ceramic Li1.3Al0.3Ti1.7(PO4)3 (LATP) nanoparticles for use in a poly­(ethylene oxide) (PEO) matrix. This network also provided structural support and enhanced the mechanical properties of the polymer matrix, which is important for a battery electrolyte. The resulting CSE membrane had room temperature ionic conductivity of 1.64 × 10–4 S/cm. Li/Li symmetric cells using this CSE showed no short circuits for 500 h cycling at a current density 0.1 mA cm–2. Control cells using standard LATP powder showed higher overpotential and dendrite failure, as did the polymer membrane with no LATP.

Layer-Structured Composite Solid-State Electrolyte with a Li1.3Al0.3Ti1.7(PO4)3-Coated Separator for High-Voltage Lithium Metal Batteries by In Situ Polymerization

“…As shown in Figure f, the characteristic peaks between 725 and 745 cm –1 could be used to distinguish whether the TFSI – anions are free or fixed. − The ratio of free TFSI – anions for LPDOL is 47.8%, which is lower than that for PDOL (59.3%). Thus, there are more free Li + cations and less free TFSI – anions in LPDOL, which might be due to the interaction between TFSI – and the LATP coating layer. , As a result, by using LATP-coated separators, the concentration polarization could be reduced effectively, and the electrochemical performance of the batteries could be improved.…”

“…Thus, there are more free Li + cations and less free TFSI − anions in LPDOL, which might be due to the interaction between TFSI − and the LATP coating layer. 35,36 As a result, by using LATPcoated separators, the concentration polarization could be reduced effectively, and the electrochemical performance of the batteries could be improved.…”

Multifunctional composite designs for structural energy storage

“…86 By integrating reinforcements with solid polymer electrolytes, substantial improvements in mechanical strength can be achieved. 66,67,83 Through the careful selection of compatible fillers and polymer matrices, this approach holds the potential to rival commercial CFRP in terms of mechanical strength. However, challenges arise with respect to electrochemical performance, as interface considerations become paramount to attain moderate rate performance and cycling stability, which are essential for high-power density solid-state batteries.…”

“…Various strategies have been explored to enhance the mechanical integrity of solid polymer electrolytes. These approaches encompass the incorporation of ceramic nanoparticles, 66 ceramic/polymer fibers, 67,68 and the integration of 3D networks 69 . For example, a noteworthy method involves a fiber‐reinforced structural electrolyte that utilizes poly(ethylene oxide)–lithium bis(trifluoromethane) sulfonimide (PEO‐LiTFSI) as the polymer electrolyte matrix, while employing lithium aluminum titanium phosphate (LATP) and glass fiber (GF) as reinforcing fillers.…”

PEO/PVDF–HFP/LLZTO Composite Solid Polymer Electrolyte for High-Performance All-Solid-State Lithium Metal Batteries

“…Nowadays, all-solid-state lithium metal batteries (ASSLMBs) have become the promising candidates due to the high safety of the solid-state electrolyte (SSE) and high energy density of the lithium metal. − SSEs are an important component in ASSLMBs, which can be categorized into three types: solid inorganic electrolytes (SIEs), solid polymer electrolytes (SPEs), and composite SPEs (CSPEs). − SIEs present high ionic conductivity, a wide electrochemical stability window (ESW), high mechanical strength, incombustibility, and a superior lithium-ion (Li + ) transfer number ( t Li + ). Unfortunately, SIEs are more brittle and exhibit poor interfacial contact with electrodes.…”