Carbon Excess C₃N: A Potential Candidate as Li-Ion Battery Material

Abstract

Xu et al.’s recent experimental work (Adv. Mater. 2017, 29, 1702007) suggested that C3N is a potential candidate as Li-ion battery with unusual electrochemical characteristics. However, the obvious capacity loss (from 787.3 to 383.3 mA h·g–1) occurs after several cycles, which restricts its high performance. To understand and further solve this issue, in the present study, we have studied the intercalation processes of Li ions into C3N via first-principle simulations. The results reveal that the Li-ion theoretical capacity in pure C3N is only 133.94 mA h·g–1, the value is obviously lower than experimental one. After examining the experimental results in detail, it is found that the chemical component of the as-generated C x N structure is actually C2.67N with N excess. In this case, the calculated theoretical capacity is 837.06 mA h·g–1, while part of Li ions are irreversibly trapped in C2.67N, resulting in the capacity loss. This phenomenon is consistent with the experimental results. Accordingly, we suggest that N excess C3N, but not pure C3N, is the proposed Li-ion battery material in Xu et al.’s experiment. To solve the capacity loss issue and maintain the excellent performance of C3N-based anode material, the C3N with slightly excess C (C3.33N), which has been successfully fabricated in the experiment, is considered in view of its relatively low chemical activity as compared with N excess C3N. Our results reveal that the C excess C3N is a potential Li-ion battery material, which exhibits the low open circle voltage (0.12 V), high reversible capacity (840.35 mA h·g–1), fast charging/discharging rate, and good electronic conductivity.

Solution‐Processable Conductive Organics via Anion‐Induced n‐Doping and Their Applications in Organic and Perovskite Solar Cells

“…[55,83] Besides that, interfacial materials with desirable charge transport capabilities could enhance charge extraction and mitigate recombination to improve device performances. [4,9,17,69,84] Upon facing the rapid progresses made from active layer semiconductors with various functionalities, such as energy level, mobility, and surface energy, [85] interfacial materials also need further advancement to match with the different active layers. In another important aspect, new solar cells, when efficiencies reaching practical level, need to consider their large scale fabrication and long-term stabilities, which also calls for stable interfacial materials with excellent solution processability and accessibilities.…”

“…Emrick et al [91][92][93] developed amine (C 60 -N) and sulfobetaine (C 60 -SB)-substituted fulleropyrrolidines as cathode interlayers, which can reduce the effective high WF metal electrodes (such as Ag, Cu, and Au) similar to conductive fullerene ETLs. Other conductive fullerene derivatives (PCBANX, [69] C 60 -4TPB, [84] and PCBB-3N-3I [94] ) with Lewis base anion-doping functionalities have been developed and independently verified from different groups. The effectiveness of WF shift and charge transport have been verified for these AIET-doped fullerenes; moreover, ESR measurements confirm the effective n-doping between anion and fullerene.…”

“…The effectiveness of WF shift and charge transport have been verified for these AIET-doped fullerenes; moreover, ESR measurements confirm the effective n-doping between anion and fullerene. [84,94] All Figure 2. ESR spectra of a) TCNQ and TCNQ/F − in solution state; b) PCBM and PCBM/F − in solution and solid state.…”

Characterization of Metal‐zeolite Composite Catalysts: Determining the Environment of the Active Phase

“…[97] Similar TPD profiles can be conducted with other adsorbate molecules, such as CO 2 , which is a Lewis acid and has been used to characterize basicity in mesoporous TS-1. [98] In addition to probing the strength of basic sites within the catalyst, the authors measure the capacity of CO 2 adsorption after acid treatment to determine if TS-1 is a viable catalyst for the cycloaddition of CO 2 to epoxides. In the following section, the characterization of metal-zeolite composite catalysts is expanded to determining the catalytic mechanism and structure under reaction conditions.…”

Synthesis and Application of Functionalized Diblock Amphiphilic Fullerene Derivatives

“…[39] Our group reported an amphiphilic diblock fullerene derivatives C 60 -4TPB to modify ZnO layer toward efficient PCE in inverted OSCs device. [40] Here, a series of new amphiphilic diblock fullerene derivatives with side chains containing different hydrophilic groups named [6,6]-Phenyl-C 61 -butyricacid--potassium-4,4′-(2-(4-(2-hydroxy-ethyl)-phenyl)-9H-fluorene-9,9-diyl)bis(butane-1-sulfonate) (C 60 -PHFBS), [6,6]-Phenyl-C 61 -butyricacid-2-(4-(9,9-bis(2-(dimethylamino)ethyl)-9Hfluoren-2-yl)-phenyl)ethan-1-ol (C 60 -2DPE), [6,6]-Phenyl-C 61butyricacid-3,3'-(2-(4-hydroxy-phenyl)-9H-fluorene-9,9-diyl) bis-(N,N,N-trimethylpropan-1-aminium)-bromide (C 60 -4HTPB), and [6,6]-phenyl-C 61 -butyricacid-2-(4-(9,9-bis(2-(2-ethoxyethoxy) ethyl)-9H-fluoren-2-yl) phenyl)ethan (C 60 -2BEFPE) were synthesized and applied as the modification layers on ZnO in inverted OSCs, as presented in Figure 1. Unlike the two fluorene conjugate structures in C 60 -4TPB, the new fullerene derivatives mentioned in this work have one fluorene conjugate structure.…”