Tailoring Ordered Porous Carbon Embedded with Cu Clusters for High‐Energy and Long‐Lasting Phosphorus Anode

Abstract

most porous carbon families only possess a single pore-type structure, [14][15][16][17][18] which makes it difficult to meet the demands due to the blockage of the simplex porous channels caused by the infiltration of RP and unsatisfied RP loading, leading to poor cycling properties. Micro-mesoporous nanostructure is beneficial to capture RP and increase the effective contact area. [19][20][21] But, the uncontrollable and disordered distribution of pores causes the heterogeneous size and agglomeration of RP, hindering the ion diffusion, and low pore volume cannot alleviate the drastic volume changes. Thus, constructing interconnected and ordered porous carbon host to exclusively confine RP and affording adequate space to clamp the volume expansion, is an effective strategy to respond to critical requirements for designing ideal carbon scaffolds as well as infiltration technology. Another hurdle that impedes the high-rate capacity of RP/C composites is that the porous carbon usually provides inferior electrical conductivity because of the sp 3hybridized CC bonding and amorphous state, leading to sluggish solid-state diffusion processes. [21] The most popular tactic is the engineering of the carbonaceous nanomaterials through iodine (I), boron(B), and nitrogen (N) doping, which could improve the reactivity and conductivity of carbon by creating heteroatoms defects. [22][23][24] Non-metallic heteroatom doping may increase the active sites in the carbon skeleton but may also create an intrinsic hurdle against charge transfer. In contrast, doping metal into the carbon supports can greatly improve its electrical conductivity as well as generate more active sites. Among them, Cu, which naturally owns the second-highest conductivity, [25] only 6% lower than the Ag, is a good choice for non-noble metal doping. Nevertheless, because metal tends to be located on the external surface of carbon in the form of aggregated particles, ions must pass through an intricate island-like structure byway to react with the guest RP during the discharge process, which aggravates the ionic and electrical resistance inevitably. Therefore, it is wise to reduce the particle size of Cu and nanoconfine it into the inside carbon layer of the porous matrix.Aiming to simultaneously utilize the excellent conductivity of Cu and the high porosity of porous carbon, an ideal RP immobilizer with dispersed Cu nanoclusters anchored to a trimodal porous carbon framework with periodic macroporesThe natural insulating property and notorious pulverization of volume variationinduced materials during cycling pares the electrochemical activity of red phosphorous (RP) for lithium/sodium-ion batteries (LIBs/SIBs). To work out these issues, a tailored trimodal porous carbon support comprising highly ordered macropores and micro-mesoporous walls embedded with copper (Cu) nanoclusters (Cu-OMC) is proposed to confine RP. The construction of highly conductive copper-carbon wall facilitates fast electrons and ions transportation, while the interconnected and ordered po...

Hoya-like Hierarchical Porous Architecture as Multifunctional Phosphorus Anode for Superior Lithium–Sodium Storage

“…Cyclic voltammetry (CV) test was conducted to expound the lithiation/delithiation reactions of the DCNM@RP anode within a potential window of 0.01–3 V, as shown in Figure a. In the initial cathodic curve, there was an irreversible broad peak detected at about 0.9 V, which can be assigned to the formation of a solid electrolyte interphase (SEI) film caused by the electrolyte decomposition. , Two cathodic peaks at 0.2 and 0.5 V were indexed to the continuous lithiation process of RP (Li + P→ Li x P, x = 1–3), whereas the reversible anodic peak at 1.32 V was associated with the delithiation process of Li x P compounds. , In the subsequent cycles, the major anodic and cathodic peaks were concentrated at 1.29 and 0.64 V, respectively, reflecting the high electrochemical stability of the DCNM@RP anode. The initial five galvanostatic charge/discharge profiles of the DCNM@RP are shown in Figure b, in which the voltage plateaus agree well with the CV results.…”

“…Moreover, the ion diffusion coefficient in these anodes can be extracted from galvanostatic intermittent titration technique (GITT) results (Figure f) according to Fick’s second law with eq : , D = 4 π τ true( m B V M M B A true) 2 true( normalΔ E S normalΔ E τ true) 2 where the calculation details of the ion migration coefficient ( D ) are described in Figure S19 (Supporting Information) and the values of D Li + are listed in Figure g. Compared with the other two anodes, the DCNM@RP anode exhibits the highest diffusion coefficient with the range of 10 –13 –10 –11 cm 2 s –1 during the whole charge and discharge process, suggesting that the uniformly dispersed micromesopores can make Li ion diffuse quickly and orderly, thus contributing to kinetically accelerate the polyphosphide redox transformation.…”

“…CV profiles are put forward in Figure 7a to expound the electrochemical behavior of the DCNM@RP anode. In the cathodic scan, the irreversible peak at 0.76 V corresponds to the decomposition of electrolyte to generate the SEI membrane, and the broad peak at the range of 0.2−0.5 V can be assigned to the stepwise sodiation from RP to Na x P and finally to Na 3 P. 20,33 In the backward process, only one major peak at 0.78 V was detected, which can be ascribed to the desodiation from Na x P compounds to RP. 40 Similar plateau traits are also observed in the typical voltage-capacity profiles (Figure 7b).…”

“…15−18 Once the active materials are filled into the internal cavity, the hollow shell with a negative radius of curvature can act as a gate to physically block them and provide extra space to perfectly mitigate the volumetric variation. 19,20 However, most of the available hollow spheres have relatively single configurations, such as a simple pore-type of one composition, 21 which induces the serious agglomeration of bulk RP residing in the inner void, increasing the resistance of solidstate diffusion. 4 Simplex physical constraints between the porous host and active species are not sufficient to maintain the cycle stability during electrochemical reactions due to the dissolution of polyphosphides.…”

“…Compared with the sorption isotherms of HM, a distinct H3-type hysteresis loop was observed at high relative pressures (0.5−1.0) (Figure 3e), suggesting the coexistence of micropores and mesopores in the as-synthesized DCNM. 20,33 Based on the Brunauer−Emmett−Teller (BET) method, the DCNM showed a high surface area of 319.6 m 2 g −1 and a large pore volume of 0.54 cm 3 g −1 , which was larger than that of HM (87.9 m 2 g −1 , 0.16 cm 3 g −1 ) (Table S1, Supporting Information). The favorable surface area and pore volume of DCNM are the consequence of the constructed uniform hollow structure and the planted micromesoporous carbon decorated layer, which is capable of conferring antiaggregation properties and improving the electrolytic accessibility within DCNM.…”