An Advanced Gel Polymer Electrolyte for Solid-State Lithium Metal Batteries.

All-solid-state lithium metal batteries (LMBs) are regarded as one of the most viable energy storage devices and their comprehensive properties are mainly controlled by solid electrolytes and interface compatibility. This work proposes an advanced poly(vinylidene fluoride-hexafluoropropylene) based gel polymer electrolyte (AP-GPEs) via functional superposition strategy, which involves incorporating butyl acrylate and polyethylene glycol diacrylate as elastic optimization framework, triethyl phosphate and fluoroethylene carbonate as flameproof liquid plasticizers, and Li7La3Zr2O12 nanowires (LLZO-w) as ion-conductive fillers, endowing the designed AP-GPEs/LLZO-w membrane with high mechanical strength, excellent flexibility, low flammability, low activation energy (0.137 eV), and improved ionic conductivity (0.42 × 10-3 S cm-1 at 20 °C) due to continuous ionic transport pathways. Additionally, the AP-GPEs/LLZO-w membrane shows good safety and chemical/electrochemical compatibility with the lithium anode, owing to the synergistic effect of LLZO-w filler, flexible frameworks, and flame retardants. Consequently, the LiFePO4/Li batteries assembled with AP-GPEs/LLZO-w electrolyte exhibit enhanced cycling performance (87.3% capacity retention after 600 cycles at 1 C) and notable high-rate capacity (93.3 mAh g-1 at 5 C). This work proposes a novel functional superposition strategy for the synthesis of high-performance comprehensive GPEs for LMBs.

Solid-State Electrolytes in Lithium-Sulfur Batteries: Latest Progresses and Prospects.

Solid-state lithium-sulfur batteries (SSLSBs) have attracted tremendous research interest due to their large theoretical energy density and high safety, which are highly important indicators for the development of next-generation energy storage devices. Particularly, safety and "shuttle effect" issues originating from volatile and flammable liquid organic electrolytes can be fully mitigated by switching to a solid-state configuration. However, their road to thecommercial application is still plagued with numerous challenges, most notably the intrinsic electrochemical instability of solid-state electrolytes (SSEs) materials and their interfacial compatibility with electrodes and electrolytes. In this review, a critical discussion on the key issues and problems of different types of SSEs as well as the corresponding optimization strategies are first highlighted. Then, the state-of-the-art preparation methods and properties of different kinds of SSE materials, and their manufacture, characterization and performance in SSLSBs are summarized in detail. Finally, a scientific outlook for the future development of SSEs and the avenue to commercial application of SSLSBs is also proposed.

A Trifunctional Separator Based on a Blockage-Adsorption-Catalysis Synergistic Effect for Li-S Batteries.

To address the obstinate problem of the shuttle effect in lithium-sulfur (Li-S) batteries, cathode materials are usually given multifunctions to immobilize sulfur, which increases the processing difficulty of cathode materials and weakens the advantage in energy density of Li-S batteries. Herein, a single-source decomposition approach is employed to synthesize a pomegranate-like nitrogenous carbon-coated ZnS (ZnS@NC) precursor that is acid etched to obtain the partially etched ZnS@NC (PE-ZnS@NC) composite. PE-ZnS@NC is coated on a commercial PP separator to a fabricate PE-ZnS@NC/PP functional separator that is used to assemble a coin cell with the sulfur/super P cathode. The 3D network carbon framework of PE-ZnS@NC provides additional active sites for electrochemical reaction and a space barrier for the diffusion of the dissolved lithium polysulfides (LPS). Well-distributed N-containing functional groups and polar ZnS could chemically anchor LPS. Also, the ZnS nanoparticles inside could facilitate a fast kinetic process by catalyzing the liquid-liquid and liquid-solid conversion. Since the shuttle effect is greatly suppressed by the synergistic trifunctions of blockage-chemisorption catalysis, PE-ZnS@NC/PP delivers remarkable electrochemical performances that a self-discharge rate of 0.4% per day is achieved in the shelving test and a capacity retention of 97.0% is gained after 50 cycles at 0.5 C, under a sulfur-areal density of around 3 mg cm-2.