Cross‐Coupled Macro‐Mesoporous Carbon Network toward Record High Energy‐Power Density Supercapacitor at 4 V

Abstract

Ionic liquids (ILs) electrolyte hold tremendous potentials to develop high‐energy‐density electric double layer capacitor due to their wide voltage windows, but are severely plagued by the sluggish mass diffusion from high viscosity and large ion size, particularly over micropore‐dominated carbon electrodes. Exploiting the carbon electrode possessing high compatibility with ILs electrolyte remains a great challenge. Herein, an emerging 3D cross‐coupled macro‐mesoporous carbon network with ultrahigh specific surface area (SSA, 2872.2 m2 g−1), N‐self doping, small‐sized mesopores (2–4 nm) and macropores (50–150 nm) is designed via a facile, versatile, and ecofriendly salt‐template strategy from the NaNO3‐gelatin biopolymer aerogel, which shows great adaptability toward high energy power density used in 4 V EMIBF4 ILs (92 Wh kg−1 is achieved at 1 kW kg−1, and notably a record high energy density of 39 Wh kg−1 is retained even at an ultrahigh power density of 200 kW kg−1). The large energy density is ascribed to the plentiful ion‐available mesoporous active sites (Smeso/SSA = 86.6%, Vmeso/Vtotal = 92.1%), while the extraordinary power density is attributed to the synergistic effects from the suitable macro‐mesoporous ion‐diffusion channels, continuous conductive network, low oxygen content (2.24%) as well as good affinity to ILs.

Synthesis Strategies of Porous Carbon for Supercapacitor Applications

“…Various salts are decomposable and thus, the decomposition gases can etch carbons to form pores. The decomposable salt is a huge family with numerous members such as zinc acetate, [78] Zn(NO 3 ) 2 , [79] NaNO 3 , [80] calcium acetate, [81] sodium acetate, [82] MgCO 3 , [83] sodium chloroacetate, [84] K 3 PO 4 , [85] NaH 2 PO 4 , [86] tetraethylorthosilicate, and potassium acid phthalate. Generally, Zn salts are regarded as a dehydration agent.…”

“…For the fabrication of carbon materials with high SSA, high pore volume, and high ratio of micropores, chemical activation methods need to be applied, which limits the commercial potential of template-based methods for the synthesis of porous carbons as SC electrodes. [80,167,168] On the other hand, the template methods can be used to fabricate high-frequency response SCs based on their macroporous structures.…”

Design of Ultra‐Microporous Carbons by Interpenetrating MF Prepolymer into PAAS Networks at Molecule Level for Enhanced Electrochemical Performance

“…And then, as P / P 0 continues to increase, the H3 type hysteresis loop is discovered, which is a emblematic feature of mesoporous carbons. Correspondingly, the nitrogen absorption‐desorption curve of PC‐MFB is also closer to type IV with a H3 style hysteresis loop when P / P 0 is greater than 0.45, which proves the existence of mesopores . The amount of adsorption of PC‐MF is minimal compared to the other two samples, which means it has a very small pore volume.…”

“…Correspondingly, the nitrogen absorption-desorption curve of PC-MFB is also closer to type IV with a H3 style hysteresis loop when P/P 0 is greater than 0.45, which proves the existence of mesopores. [26] The amount of adsorption of PC-MF is minimal compared to the other two samples, which means it has a very small pore volume. The SSA of UMC-IPNs, calculated by Brunauer-Emmett-Teller theory, [27] is 1551 m 2 g À 1 , which is 11 times of PC-MFB (143 m 2 g À 1 ) synthesized under the same conditions, and much larger than PC-MF (it is only 15 m 2 g À 1 ).…”

Mesoporous Carbons Templated by PEO‐PCL Block Copolymers as Electrode Materials for Supercapacitors

“…The energy density will be restricted if the pore sizes are distributed only in the micropore zone;a ccordingly,t he regulation of pore sizes, or even pore structures, remains achallenge. [18] Several porous carbons with various morphologies or pore structures have been developed for matching with electrolytes in supercapacitors, including curled graphenes, [19] templated carbons, [20] hierarchical porouscarbons, [21] and others.…”