Flexible metal–organic frameworks as superior cathodes for rechargeable sodium-ion batteries

Abstract

Flexible metal–organic frameworks composed of Prussian blue analogues on a highly conductive carbonfiber paper have been synthesized and utilized as attractive hosts for sodium ion storage at ambient temperature.

Recent Progress in Metal–Organic Frameworks and Their Derived Nanostructures for Energy and Environmental Applications

“…[72] The specific surfacea rea of ZIF-C is 1251 m 2 g À1 ,w hich is almost four times that of the ACN composite;h owever,t he capacity and rate performance of ZIF-C in SIBs are much worse than those of the ACN composite. [76] The obtained FeFe(CN) 6 /carbon cloth composites demonstrate ac apacity of 82 mA hg À1 at 0.2 C and good capacity retention of 81.2 %o ver 1000 cycles. Therefore, the nitrogen-doping level plays ac rucial role in determining the electrochemical performances in SIBs.…”

“…[75] After 50 electrochemical cycles,t he optimal sample (CHO-1) displays ac apacity of 415 mA hg À1 at 50 mA g À1 and about 212 mA hg À1 after 400 cycles at 1Ag À1 ,a nd remainsa bout 165 mA hg À1 after 1000 cycles at 2Ag À1 .M ore recently,N ie et al reportedaflexible cathode materialc omposed of Prussian blue analogue (FeFe(CN) 6 )/carbon cloth for applicationi nS IBs. [76] The obtained FeFe(CN) 6 /carbon cloth composites demonstrate ac apacity of 82 mA hg À1 at 0.2 C and good capacity retention of 81.2 %o ver 1000 cycles.…”

Flexible Na batteries

“…This can result in two possible failure modes of flexible cathodes: one is that carbonaceous substrates react with O 2 in the air environment, while the other is that transition metals are reduced by the carbonaceous substrates in an inert gas environment. 30 Copyright 2015, The Royal Society of Chemistry. Graphene is a promising material for flexible substrates due to its mechanical flexibility, high electrical conductivity, large specific surface area, etc.…”

“…Beyond the above two-step process of fabricating cathode materials on carbonaceous substrates, composite electrodes consisting of the flexible Prussian blue analogue FeFe(CN) 6 /carbon cloth were synthesized via a simple solution precipitation reaction at an elevated temperature of 60 C. 30 Typically, the K 3 Fe(CN) 6 and FeCl 3 solutions and carbon cloth substrates were mixed and maintained at 60 C for 6 hours, during which time FeFe(CN) 6 nanoparticles could directly grow on the conductive carbon cloth, forming an integrated electrode as shown in Figure 2C. This method can ensure intimate contact and fast electron transport between carbon fibers and the electrode materials.…”

“…Reproduced with permission. 30 Copyright 2015, The Royal Society of Chemistry. D, SEM and transmission electron microscopy (TEM) images of Na 3 V 2 (PO 4 ) 3 /RGO paper composite electrode.…”