A 3D‐Printed Proton Pseudocapacitor with Ultrahigh Mass Loading and Areal Energy Density for Fast Energy Storage at Low Temperature

Abstract

The sluggish ionic transport in thick electrodes and freezing electrolytes has limited electrochemical energy storage devices in lots of harsh environments for practical applications. Here, a 3D‐printed proton pseudocapacitor based on high‐mass‐loading 3D‐printed WO3 anodes, Prussian blue analog cathodes, and anti‐freezing electrolytes is developed, which can achieve state‐of‐the‐art electrochemical performance at low temperatures. Benefiting from the cross‐scale 3D electrode structure using a 3D printing direct ink writing technique, the 3D‐printed cathode realizes an ultrahigh areal capacitance of 7.39 F cm−2 at a high areal mass loading of 23.51 mg cm−2. Moreover, the 3D‐printed pseudocapacitor delivers an areal capacitance of 3.44 F cm−2 and excellent areal energy density (1.08 mWh cm−2). Owing to the fast ion kinetics in 3D electrodes and the high ionic conductivity of the hybrid electrolyte, the 3D‐printed supercapacitor delivers 61.3% of the room‐temperature capacitance even at −60 °C. This work provides an effective strategy for the practical applications of energy storage devices with complex physical structure at extreme temperatures.

Revealing the Effect of the [CoO]6 Microstructure in Pseudocapacitance by Controlled Delithium of LiCoO2

“…As shown in Figure c, the b -values determined by fitting the anodic and cathodic data of LiCO, Li 0.96 CO, Li 0.92 , Li 0.87 CO, Li 0.75 CO, and Li 0.50 CO are 0.87–0.78, 0.70–0.75, 0.68–0.75, 0.79–0.68, 0.74–0.79, and 0.74–0.75, respectively (Figures S16–20). This verifies the expression of both mechanisms within L 1– x CO, and the Li 0.75 CO electrode exhibits enhanced contribution of diffusion-controlled mechanisms in comparison to the LiCO 2 electrode. , The increased exposure of the cobalt–oxygen octahedron leads to a phenomenon that allows higher diffusion control, probably due to the enhanced redox capacity of Co 4+ , which has a stronger ability to gain electrons. In addition, electrochemical impedance spectroscopy (EIS) was used to analyze the charge-transfer resistance ( R ct ) and ion diffusion ( R s ) of the samples (Figure d and Table S3).…”

“…In contrast, as the b-value approaches 1, the energy-storage process is characterized by capacitance. As shown in Figure 4c, the b-values determined by fitting the anodic and cathodic data of LiCO, Li 29,30 The increased exposure of the cobalt−oxygen octahedron leads to a phenomenon that allows higher diffusion control, probably due to the enhanced redox capacity of Co 4+ , which has a stronger ability to gain electrons. In addition, electrochemical impedance spectroscopy (EIS) was used to analyze the charge-transfer resistance (R ct ) and ion diffusion (R s ) of the samples (Figure 4d and Table S3).…”

A simple route to functionalized porous carbon foams from carbon nanodots for metal-free pseudocapacitors

“…Hence, the charges are situated at the interface between the electrode and electrolyte, and can be driven by increased voltage in aqueous electrolytes. 58 The diffusion of 3D-tsSC300 in organic electrolytes is impeded by p-p interactions, resulting in a decrease in diffusion resistance. Consequently, coupling with organic electrolytes eliminates these unreacted ligands enhancing the accessibility of the electrode surfaces and micropores to the electrolyte, meanwhile increasing the capacitance by voltage broadening.…”

New approaches to three-dimensional positive electrodes enabling scalable high areal capacity

“…11,12 However, it oen suffers from poor electrochemical performance and weak mechanical stability with increasing electrode thickness and areal mass loading due to sluggish electron/ion transportation. 13,14 To address these limitations, novel three-dimensional (3D) electrodes with conductive porous structures are extensively explored, and diverse methods including magnetic, 15 wood templating, [16][17][18] freeze casting, [19][20][21] spark plasma sintering, 22 3D printing, [23][24][25] wet calendaring, 26 and powder extrusion molding (PEM) 27 have been developed to increase the active material loading and enhance ion transportation. Take LiFePO 4 (LFP), the safest, cost-effective, and environmentally benign candidate material for commercial LIB cathodes, as an example, which has always been plagued with poor conductivity.…”