A General Synthesis of Mesoporous Hollow Carbon Spheres with Extraordinary Sodium Storage Kinetics by Engineering Solvation Structure

Abstract

Porous and hollow carbon materials have great superiority and prospects in electrochemical energy applications, especially for surface charge storage due to the high active surface. Herein, a general strategy is developed to synthesize mesoporous hollow carbon spheres (MHCS) with controllable texture and compositions by the synergistic effect of dopamine polymerization and metal catalysis (Cu, Bi, Zn). Mesoporous MHCS–Cu and MHCS–Bi are regular spheres, while mesoporous MHCS–Zn possesses an inward concave texture, and simultaneously has a very high surface area of 1675.5 m2 g‐1 and lower oxygen content through the catalytic deoxygenation effect. MHCS–Zn displays an exceptional sodium storage kinetics and excellent long cycling life with 171.9 mAh g‐1 after 2500 cycles at 5 A g‐1 in compatible ether‐based electrolytes. Such electrolyte enables enhanced solvated Na+ transport kinetics with appropriate electrostatic interactions at the surface of carbon anode as revealed by molecular dynamics simulations and molecular surface electrostatic potential calculations. Such an anode also displays basically constant capacity working at 0 °C, and still delivers 140 mAh g‐1 at 3 A g‐1 under ‐20 °C. Moreover, MHCS–Zn anode is coupled with Na3V2(PO4)3 cathode to construct a hybrid capacitor, which exhibits a high energy density of 145 Wh Kg‐1 at a very high power of 8009 W kg‐1.

Modulating Intrinsic Defect Structure of Fibrous Hard Carbon for Super‐Fast and High‐Areal Sodium Energy Storage

“…Obviously, there is no plateau for the first GCD profiles, indicating the capacitance‐dominated Na + storage mechanism. [ 36 ] However, note that a slop region between 2.0 and 2.3 V in the charge curve is regarded as the contribution of bonding between sodium and oxygen, [ 37 ] which has been reported in previous literatures. [ 37–40 ] Figure 3b compares the rate capability of TC samples, corresponding charge‐discharge curves at different current densities are presented in Figure S15 (Supporting Information).…”

“…[ 36 ] However, note that a slop region between 2.0 and 2.3 V in the charge curve is regarded as the contribution of bonding between sodium and oxygen, [ 37 ] which has been reported in previous literatures. [ 37–40 ] Figure 3b compares the rate capability of TC samples, corresponding charge‐discharge curves at different current densities are presented in Figure S15 (Supporting Information). In specific, the TC‐900 exhibits superior rate capability with a high reversible capacity of 222.2 mAh g −1 at 50 A g −1 , outperforming the most of HCs reported in the previous literatures.…”

Organic Phosphorescent Hopper‐Shaped Microstructures

“…Low-dimensional well-ordered crystals with advantages of sizedependent optical properties, controllable structural synthesis, quantum size effect, and rapid response to external stimuli, hold promising potential in advanced optoelectronic applications. [1][2][3][4] Compared with microstructure with flat surfaces, concave hopper-shaped microstructure has larger surface-to-volume ratio, low density, high loading capacity, and higher surface activity, showing great promise in a wide range of fields in catalysis, [5][6][7] drug delivery, [8] miniature vessels, [9] as well as gas sensors. [10] So far, most of the hopper-shaped microstructures are focused on inorganic materials, such as noble metals, semiconductors and perovskites, etc.…”