Mechanism of high Li-ion conductivity in poly(vinylene carbonate)-poly(ethylene oxide)cross-linked network based electrolyte revealed by solid-state NMR

Solid polymer electrolytes(SPEs)have become increasingly important in advanced lithium-ion batteries(LIBs)due to their improved safety and mechanical properties compared to organic liquid electrolytes.Cross-linked polymers have the potential to further improve the mechanical property without trading off Li-ion conductivity.In this study,focusing on a recently developed cross-linked SPE,i.e.,the one based on poly(vinylene carbonate)-poly(ethylene oxide)cross-linked network(PVCN),we used solid-state nuclear magnetic resonance(NMR)techniques to investigate the fundamental interaction between the chain segments and Li ions,as well as the lithium-ion motion.By utilizing homonuclear/heteronuclear correlation,CP(cross-polarization)kinetics,and spin-lattice relaxation experiments,etc.,we revealed the structural characteristics and their relations to lithium-ion mobilities.It is found that the network formation prevents poly(ethylene oxide)chains from crystallization,which could create sufficient space for segmental tumbling and Li-ion co nductio n.As such,the mechanical property is greatly improved with even higher Li-ion mobilities compared to the poly(vinylene carbonate)or poly(ethylene oxide)based SPE analogues.

An Endotenon Sheath-Inspired Double-Network Binder Enables Superior Cycling Performance of Silicon Electrodes

Silicon(Si)has been regarded as an alternative anode material to traditional graphite owing to its higher theoretical capacity(4200 vs.372 m Ah g;).However,Si anodes suffer from the inherent volume expansion and unstable solid electrolyte interphase,thus experiencing fast capacity decay,which hinders their commercial application.To address this,herein,an endotenon sheathinspired water-soluble double-network binder(DNB)is presented for resolving the bottleneck of Si anodes.The as-developed binder shows excellent adhesion,high mechanical properties,and a considerable self-healing capability mainly benefited by its supramolecular hybrid network.Apart from these advantages,this binder also induces a Li;N/Li F-rich solid electrolyte interface layer,contributing to a superior cycle stability of Si electrodes.As expected,the DNB can achieve mechanically more stable Si electrodes than traditional polyacrylic acid and pectin binders.As a result,DNB delivers superior electrochemical performance ofSi/Li half cells and Li Ni;Co;Mn;O;/Si full cells,even with a high loading of Si electrode,to traditional polyacrylic acid and pectin binders.The bioinspired binder design provides a promising route to achieve long-life Si anode-assembled lithium batteries.

Correction to:An endotenon sheath‑inspired double‑network binder enables superior cycling performance of silicon electrodes

The original version of this article unfortunately contained some mistakes.1.The authors found that the data unit in Fig.3a–f is wrong.The corrected version of Fig.3 is given below:2.The authors found that explanation of the data lines in Fig.2e is wrong.The corrected version of the explanation of Fig.2e is given below:The DNB can endure approximately 300%stretching and withstand stress up to about 1.5 MPa,as shown in Fig.2e.

The influence of extreme cold ambient temperature on out of hospital cardiac arrest: A systemic review and meta-analysis

Objective:Many researches have demonstrated the effects of the extreme cold ambient temperature on the risk of out-of-hospital cardiac arrest(OHCA);yet,the results have been inconsistent.We performed a meta-analysis to evaluate whether extreme cold ambient temperature is related to OHCA.Methods:We searched for time-series studies reporting associations between extreme cold ambient temperature and OHCA in PubMed,web of science and Cochrane database.Results:Six studies involving 2337403 cases of OHCA were qualified for our meta-analysis.The odds ratio(OR)of OHCA was significantly increased in extreme cold weather(defined as the 1st or 5th centile temperature year-round)compared to reference temperature(as the 25th centile temperatures or daily mean temperature with minimum risk of OHCA)(OR=1.49,95%CI 1.18-1.88).The subgroup analysis for the elderly and the female failed to detect the influence of extreme cold weather on OHCA,the ORs are 1.25(95%CI 0.89-1.75)and 1.19(95%CI 0.87-1.64),respectively.Conclusion:The risk of OHCA is significantly higher in extreme cold ambient temperatures than in reference temperature,according to a relative temperature scale with percentiles of the region-specific temperature distribution.

How Do Polymer Binders Assist Transition Metal Oxide Cathodes to Address the Challenge of High‑Voltage Lithium Battery Applications?

Research on the chemistry of high-energy-density transition metal oxide cathodes(TMOCs)is at the forefront in the pursuit of lithium-ion batteries with increased energy density.As a critical component of these cathodes,binders not only glue cathode active material particles and conducting carbons together and to current collectors but also play pivotal roles in building multiscale compatible interphases between electrolytes and cathodes.In this review,we outline several vital design considerations of high-voltage binders,several of which are already present in traditional binder design that need to be highlighted,and systematically reveal the chemistry and mechanisms underpinning such binders for in-depth understanding.Further optimization of the design of polymer binders to improve battery performance is also discussed.Finally,perspec-tives regarding the future rational design and promising research opportunities of state-of-the-art binders for high-voltage TMOCs are presented.

An in-situ generated composite solid-state electrolyte towards high-voltage lithium metal batteries

The solid-state electrolyte(SSE) has promising applications in next-generation lithium(Li) metal batteries(LMBs) because of its significantly enhanced safety and more compatible interface characteristics than flammable traditional liquid electrolytes.However,only a few attempts have achieved high-performance high-voltage LMBs,which is attributed to the fact that both high ionic conductivity and good compatibility with electrodes can hardly be achieved simultaneously.Herein,a composite solid-state electrolyte(CSE) based on star-shaped siloxane-based polymer electrolyte coupled with Li_(6.75)La_(3)Zr_(1.75)Ta_(0.25)O_(12)(LLZTO)ceramic fillers is designed and prepared through a facile in-situ polymerization method.The obtained CSE exhibits high ionic conductivity(i.e.,1.68 × 10^(-4) S cm^(-1) at a temperature of 60 ℃),superior anodic stability,and high Li-ion transference number(i.e.,0.53) because of the multifunctional synergistic effect of the polymer electrolyte with LLZTO ceramic fillers.Moreover,the as-developed CSE shows excellent compatibility with Li anodes.As a result,the as-developed CSE enables the development of long-life 4.4-V-class solid-state LMBs with a Li CoO_(2) cathode,with 79.7% capacity retention and 99.74% average Coulombic efficiency after 500 cycles at a 0.5 C rate.Postmortem analysis of cycled batteries confirms that such superior battery performance can be mainly ascribed to the formation of a compatible electrode/electrolyte interface.Furthermore,excellent safety features can be observed in LiCoO_(2)/Li pouch batteries.This work provides an important guide for the rational design of SSEs for high-voltage LMBs.

A polymer electrolyte with a thermally induced interfacial ion-blocking function enables safety-enhanced lithium metal batteries

Lithium metal batteries(LMBs)have recently been revitalized as one of the most promising electrochemical energy storage systems,owing to the ultrahigh specific capacity(3860 mAh g^(-1))and ultralow potential(-3.04 V vs.standard hydrogen electrode)of lithium metal anodes.However,safety hazards originating from lithium dendrite growth and pulverization during cycling and thermal stimulation present significant challenges to the practical application of LMBs.To address this issue,we have developed an in situ polymer electrolyte with thermally induced interfacial ion-blocking ability.We demonstrate that the repolymerization and deposition of residual vinylene carbonate in the as-prepared electrolyte under thermal abuse predominantly results in thermally induced ion blocking at the solid electrolyte interface,thus achieving superior LMB safety.The developed polymer electrolyte also yields superior cyclability in LMBs.This design philosophy provides a good paradigm for improving the safety of LMBs.