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For next generation lithium batteries, solid polymer electrolytes (SPEs) are essential to meet the challenges of higher safety standards, higher specific energy, and easy processing. Linear polyethylene glycol (PEG) based SPEs are by far the most investigated systems for these requirements. However, the weak mechanical properties, high crystallinity, and consequently moderate ionic conductivity prevent these systems from being used in electrochemical storage devices. We address the question of the influence of the polymer architecture on the above properties by synthesizing bottlebrush copolymers carrying PEG side chains and comparing their electrochemical properties and ionic conductivity with those of the respective linear PEG polymers. For obtaining bottlebrush polymers, first methacrylate (PEGMEMA) and norbornene (Nb-PEGME) macromonomers carrying PEG side chains were synthesized and polymerized using either free radical polymerization or ring-opening metathesis polymerization (ROMP), respectively. We ...

Solid polymer electrolytes (SPEs) with good thermal, mechanical and electrochemical cycling stability are required for application in all-solid-state lithium metal batteries (LMBs) using non-intercalating Li metal anodes at room temperature. In this context, the polymer architecture plays a significant role in influencing the above parameters. Therefore, we studied systematically Poly(MA)m-graft-PEGME2k in comparison to the linear poly(ethylene oxide) (PEO) homopolymer as SPEs in all-solid-state LMBs using LiFePO4 as a cathode. Additionally, nanocomposite electrolytes using bottlebrush (SPNE1) and PEO (SPNE2) with improved mechanical and electrochemical properties were prepared by adding different amounts of TiO2 nanoparticles. Among them, the SPNE1-10 (with 10 wt% TiO2) showed a homogenous distribution of nanoparticles throughout the polymer matrix, exhibited a good ionic conductivity of 3·10–5 at 25 ᴼC and 5.2·10–4 at 70 ᴼC, as well as a high electrochemical stability of up to 5.2 V vs. Li/Li+. Moreover, the symmetric Li/SPNE1-10/Li cells displayed a constant current up to 40 cycles without any fluctuations indicating good interfacial compatibility between the electrode and electrolyte. Furthermore, extended distribution of relaxation times (eDRT) studies provide evidence of a stable solid-electrolyte interface (SEI) layer formation, which is further supported by ex-situ X-ray photoelectron spectroscopy (XPS) analysis of the cycled lithium surface. The LMBs with the SPNE1-10 electrolyte delivered a high discharge capacity of 132 mAh g−1 at 70 ᴼC at a 0.2C. Even, when the current rate was increased to 2C, the cell maintained a good discharge capacity after 400 cycles. The SPNE1-10 nanocomposite based on the bottlebrush polymer outperforms considerably the SPNE2-10 consisting of linear PEO for the whole temperature range from 25 to 80 ᴼC enabling efficient all solid-state LMBs using SPEs below 70 ᴼC.

One-dimensional patchy nanostructures are interesting materials due to their excellent interfacial activity and their potential use as carrier for functional nanoparticles. Up to now only wormlike crystalline-core micelles (wCCMs) with a nonfunctional patchy PS/PMMA corona were accessible using crystallization-driven self-assembly (CDSA) of polystyrene-block-polyethylene-block-poly(methyl methacrylate) (SEM) triblock terpolymers. Here, we present a facile approach toward functional, patchy wCCMs, bearing tertiary amino groups in one of the surface patches. The corona forming PMMA block of a SEM triblock terpolymer was functionalized by amidation with different N,N-dialkylethylenediamines in a polymer analogous fashion. The CDSA of the functionalized triblock terpolymers in THF was found to strongly depend on the polarity/solubility of the amidated PMMA block. The lower the polarity of the amidated PMMA block (increased solubility), the higher is the accessible degree of functionalization upon which define...

Solid state electrolytes based on polymer or ceramic materials are a safe alternative to liquid electrolytes based on organic solvents. Yet their ionic conductivity does not meet the required specification for state-of-the-art lithium-ion batteries. Furthermore, their conductivity mechanisms and interfacial behavior are not fully understood, making in-depth electrical characterization necessary. The calculation of the Distribution of Relaxation Times from the impedance spectrum of an electrochemical component is a powerful approach to gain insight into the processes and mechanisms responsible for the electrical and electrochemical behavior. Here we introduce an extended Distribution of Relaxation Times to avoid error-prone preprocessing. This method includes non-resistive-capacitive elements in its impedance function to overcome the constraints usually limiting the Distribution of Relaxation Times. In this study we investigated solid polymer and ceramic electrolytes regarding their conductivity mechanisms, charge transfer mechanisms and interphase formation. While the materials all possess one major conductivity mechanism, significant differences in charge transfer and interphase behavior were observed. In the case of solid polymer electrolytes, poly (ethylene glycol) bottlebrush polymers were prepared using two different boron-based lithium salts. Additionally, solid polymer electrolytes based on triethylene glycol grafted onto a poly (glycidyl propargyl ether) backbone blended with lithium bis(trifluoromethanesulfonyl)imide were compared to a similar single-ion conducting solid polymer electrolyte with the bis(trifluoromethanesulfonyl)imide anion spatially fixed to the backbone by sequential co-click synthesis. For the ceramic electrolyte, Li5·6Al0·3La3Zr1·5Ta0·5O12 powder was synthesized via a mixed oxide route and the dense ceramic electrolytes layers were fabricated by the Powder Aerosol Deposition Method. The produced layers were post-treated at 400 °C and the influence of the thermal annealing atmosphere on the conductivity of the solid electrolytes was investigated. In this study, we present the feasibility of the extended Distribution of Relaxation Times for the characterization of the investigated materials. The time-dependent formation of an interphase layer in the polymer electrolytes is identified, separated from the charge transfer process and quantified. For the ceramic electrolyte, the influence of the annealing is depicted and the charge transfer reaction is detected.