The exploration of low-strain and high-performance electrode is a crucial issue for aqueous potassium-ion battery(AKIB).Herein,a novel potassium mediated iron/manganese binary hexacyanoferrate nano-cuboid,i.e.,KxFeyMn1-y[Fe(CN)6]·nH2O(KFeMnHCF)nanocuboid,with the concentration-gradient(CG)structure is designed as a high-performance cathode for AKIB.Internal the CG-KFeMnHCF nanocuboids,the manganese content gradually decreases from the interior to the surface and the iron content changes reverse,resulting in the concentration-gradient structure.Both experimental and finite element simula-tion(FEA)results demonstrate the lower internal stress and better mechanical characteristics of CG struc-tured nanocuboid than the homogenous structured one upon ion intercalation/deintercalation processes.Meanwhile,the electrochemical testing and theoretical calculation(DFT)results disclose the substitution of Fe to Mn in the KMnHCF crystal results in the enhanced electronic conductivity,potassium migration and electrochemical kinetics.Taken both advantages from the well-designed architecture and optimized crystal structure,the CG-KFeMnHCF achieves the superior rate capability and ultrahigh stability in aque-ous potassium ion system.In particular,the CG-KFe0.31Mn0.69HCF achieves the best comprehensive prop-erties among all the samples.The full AKIBs based on CG-KFe0.31Mn0.69HCF cathode achieves the high energy density(83 Wh kg-1),superior power density,high capacity retention(83％)over high-rate long-term cycles,good adaptation to a wide temperature range(-20 to 40℃)and high reliability even under outside deformations.Therefore,this work not only provides a new clue to design the high-performance cathode,but also promotes the applications of AKIBs for diverse electronics and wide work-ing environments.

Key Laboratory for Photonic and Electronic Bandgap Materials,Ministry of Education,College of Chemistry and Chemical Engineering,Harbin Normal University,Harbin 150001,Heilongjiang,China;College of Materials Science and Chemical Engineering,Harbin Engineering University,Harbin 150001,Heilongjiang,China

[1]Yutong Lin;Bing Han;Donglan Zhang;Xueya Liu;Zili Wang;Zhengyu Wang;Liang Si;Sen Zhang;Chao Deng-.Low-strain binary hexacyanoferrate nanocuboids with concentration-gradient structure towards fast and durable energy storage)[J].能源化学,2022(11):72-84

nanocuboids,AKIB,KxFeyMn1,KFeMnHCF,nanocuboid,KMnHCF,KFe0,31Mn0,69HCF,AKIBs

Low,strain,binary,hexacyanoferrate,concentration,gradient,towards,fast,durable,energy,storage,exploration,performance,electrode,crucial,issue,aqueous,potassium,battery,Herein,novel,mediated,manganese,CN,nH2O,CG,designed,cathode,Internal,content,gradually,decreases,from,interior,surface,changes,reverse,resulting,Both,experimental,finite,element,simula,FEA,results,demonstrate,lower,internal,stress,better,mechanical,characteristics,than,homogenous,structured,one,upon,deintercalation,processes,Meanwhile,electrochemical,testing,theoretical,calculation,DFT,disclose,substitution,crystal,enhanced,conductivity,migration,kinetics,Taken,both,advantages,well,architecture,optimized,achieves,superior,capability,ultrahigh,stability,system,particular,best,comprehensive,prop,erties,among,samples,full,density,Wh,power,capacity,retention,over,long,term,cycles,good,adaptation,wide,temperature,range,reliability,even,under,outside,deformations,Therefore,this,work,not,only,provides,new,clue,but,also,promotes,applications,diverse,electronics,environments

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