Solid polymer electrolytes(SPEs)are urgently required for achieving practical all-solid-state lithium metal batteries(ASSLMBs)but remain plagued by low ionic conductivity.Herein,we propose a strategy of salt polarization to fabricate a highly ion-conductive SPE by employing a high-dielectric polymer that can interact strongly with lithium salts.Such a polymer with large dipole moments can guide lithium cations(Li+)to be arranged along the chain,forming a continuous pathway for Li+hopping within the SPE.The as-fabricated SPE,poly(vinylidene difluoride)(PVDF)-LiN(SO2F)2(LiFSI),has an extraordinarily high dielectric constant(up to 108)and ultrahigh ionic conductivity(0.77×10-3 S cm-1).Based on the PVDF-LiFSI SPE,the assembled Li metal symmetrical cell shows excellent Li plating/stripping reversibility at 0.1 mA cm-2,0.1 mAh cm-2 over 1500 h;the ASS LiFePO4 batteries deliver long-term cycling stability at 1 C over 350 cycles(2.74 mg cm-2)and an ultralong cycling lifespan of over 2600 h(100 cycles)with high loading(11.5 mg cm-2)at 28℃.First-principles calculations further reveal the ion-dipole interactions-controlled conduction of Li+in PVDF-LiFSI SPE along the PVDF chain.This work highlights the critical role of dielectric permittivity in SPE,and provides a promising path towards high-energy,long-cycling lifespan ASSLMBs.

Qi Kang;Yong Li;Zechao Zhuang;Dingsheng Wang;Chunyi Zhi;Pingkai Jiang;Xingyi Huang

Department of Polymer Science and Engineering,Shanghai Key Laboratory of Electrical Insulation and Thermal Ageing,State Key Laboratory of Metal Matrix Composites,Shanghai Jiao Tong University,Shanghai 200240,China;Institute of Applied and Physical Chemistry and Center for Environmental Research and Sustainable Technology,University of Bremen,Bremen 28359,Germany;Department of Chemistry,Tsinghua University,Beijing 100084,China;Department of Materials Science and Engineering,City University of Hong Kong,Hong Kong 999077,China

能源化学

[1]Qi Kang;Yong Li;Zechao Zhuang;Dingsheng Wang;Chunyi Zhi;Pingkai Jiang;Xingyi Huang-.Dielectric polymer based electrolytes for high-performance all-solid-state lithium metal batteries)[J].能源化学,2022(06):194-204

ASSLMBs,Li+hopping,LiN,SO2F,LiFSI

Dielectric,polymer,electrolytes,performance,all,solid,state,lithium,metal,batteries,Solid,SPEs,are,urgently,required,achieving,practical,but,remain,plagued,by,low,ionic,conductivity,Herein,we,propose,strategy,polarization,highly,conductive,employing,dielectric,that,can,strongly,salts,Such,large,dipole,moments,guide,cations,be,arranged,chain,forming,continuous,pathway,within,fabricated,vinylidene,difluoride,PVDF,has,extraordinarily,constant,up,ultrahigh,Based,assembled,symmetrical,shows,excellent,plating,stripping,reversibility,mAh,over,LiFePO4,deliver,term,cycling,stability,cycles,ultralong,lifespan,loading,First,principles,calculations,further,reveal,interactions,controlled,conduction,Li+in,This,work,highlights,critical,role,permittivity,provides,promising,towards,energy

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