High-rate and ultralong-stable potassium-ion batteries based on antimony-nanoparticles encapsulated in nitrogen and phosphorus co-doped mesoporous carbon nanofibers as an anode material

Strategies to Hierarchical Porosity in Carbon Nanofiber Webs for Electrochemical Applications

“…The nitrogen adsorption/desorption isotherms of all the investigated CNFs showed however very low S BET values (below 20 m 2 •g −1 , see * in column 2 of Table 2), almost unchanged compared to the reference PAN-CNFs (Table 2). This result, apparently in contrast with the micrographs of Figure 3 showing pores of different size in the prepared CNFs and in contrast with previous reports using the same templates and similar synthesis conditions [6,14,[28][29][30]34], demonstrates that the obtained porosity is closed, and not accessible from outside the CNFs. This observation may be due to the partial collapse of the percolating porous network formed during the thermal removal of the template or porogen [34].…”

“…Other templates including Prussian blue analogues [24] and metal organic frameworks [25][26][27] have been used in conjunction with polymer precursors, conferring both porosity and heteroatom doping to CNFs obtained by electrospinning and carbonization. Sacrificial polymers or organic molecules such as polymethyl methacrylate (PMMA) [6,14,[28][29][30], polyvinylpyrrolidone (PVP) [31,32], poly(ethylene oxide) [33], Nafion ® [34], polysulfone [35], polystyrene [36], poly-L-lactic acid [37] and beta-cyclodextrin [38] can also be spun together with the main carbon precursor (any polymer forming conductive carbon with high yield during pyrolysis), allowing the formation of porous CNFs upon their removal by solvent or thermal treatment. Different kinds of templates can further be combined to produce hierarchical porosity, which is crucial for the transport of different species (ions, gases, liquids) in the electrodes of various electrochemical devices.…”

Urchin‐Type Architecture Assembled by Cobalt Phosphide Nanorods Encapsulated in Graphene Framework as an Advanced Anode for Alkali Metal Ion Batteries

“…Moreover, when cycled at 400 mA g −1 , the membrane electrode exhibits a reversible capacity of 62 mAh g −1 after 250 cycles with 60 % capacity retention of the 2nd cycle capacity (Figure S14). Comparatively speaking, the potassium storage performance of the membrane is inferior to its lithium and sodium storage properties, which may be attributed to the larger radius of K + (0.136 nm) compared to Li + (0.076 nm) and Na + (0.102 nm), resulting in relatively worse reaction kinetics during cycling [39, 40] …”

Enabling Superior Electrochemical Properties for Highly Efficient Potassium Storage by Impregnating Ultrafine Sb Nanocrystals within Nanochannel‐Containing Carbon Nanofibers

“…[15] Recently,improved electrochemical properties have been enabled by downsizing Sb particles and integrating them with the carbon networks. [16][17][18] Nonetheless,a lthough these strategies are effective in accommodating the volume change and enhancing the ionic and electronic transport, it remains challenging to impart long cycle life and high rate performance.T his is due largely to the fact that nanoarchitectured Sb unavoidably tends to fracture and aggregate,d issociate from the carbon framework, and decrease the electronic transportation paths during the charging and discharging processes. [19] On the other hand, the use of hierarchically porous structures has been demonstrated to remarkably accelerate the electronic and ionic transfer of active materials and in turn improving the cycling stability and rate property for secondary batteries.…”