Design of metal phosphite decorated sponge materials for high‐performance flexible battery‐type supercapacitors

Abstract

In this work, iron and zinc phosphite [FeP and Zn 3 P 2 (ZnP)] crystals were individually decorated on a flexible, freestanding, and three-dimensional (3D) graphene sponge material (GSM) through a facile and cost-effective electrodeposition method. With the synergistic effect between metal phosphite (MP) particles and graphene, 3D FeP/GSM and ZnP/GSM electrodes displayed excellent electrochemical performances with high specific capacitances of 1872 and 908 F/g at a current density of 1 A/g and remarkable cycling stabilities (85% and 70% retention after 10 000 cycles), respectively. Owing to their superior properties, two asymmetric supercapacitor (ASC) circuits were assembled by employing FeP/GSM and ZnP/GSM as the positive electrodes and GSM as the negative electrode. The FeP/GSM//GSM and ZnP/GSM//GSM ASCs exhibited high energy densities of 265 and 62 Wh/kg with high power densities of 5545 and 3050 W/kg, respectively. Furthermore, as-designed devices showed great stability as retaining 80% and 70% of their initial capacitance after a consecutive 10 000 cycles of galvanostatic charge-discharge processes. These results demonstrated that MP/GSMs can be used as promising electrode materials for flexible ASC applications.

In‐suit synthesis of FeP/C/CNT composites with excellent performance in supercapacitors and lithium‐ion batteries

“…In addition, as shown in Figure 7f, the capacity retention of the asymmetric supercapacitor Ni 2 P@C/CNT//FeP/C/CNT‐2 after 10,000 cycles is 61 %, indicating that the device has good cycling stability. Compared with reported capacitors such as MnF 2 //AC, [28] NR‐NiF 2 //AC, [29] Mn 3 O 4 ‐rGO//FeP@PGNPC, [30] FeP/GEM//GSM, [31] and CoP/FeP 4 , [32] Ni 2 P@C/C/CNT//FeP/C/CNT‐2 asymmetric capacitors exhibit strong energy storage performance (Table 1), which suggests that the device has potential for certain applications.…”

“…The cathodic and anodic peaks on the curve are related to the charge-discharge reactions of FeP + xLi + + xe À $ Li x FeP and Li x FeP + (3À x)Li + + (3x)e À $ Li 3 P + Fe. [33] The reduction peak at 1.3 V is generated by Mn 3 O 4 -rGO//FeP@PGNPC 112 W h kg À 1 /850 W kg À 1 61 W h kg À 1 /17 kW kg À 1 5000 cycles/90 %/-A g À 1 [30] FeP/GEM//GSM 265 W h kg À 1 /2.6 kW kg À 1 56 W h kg À 1 /5.5 kW kg À 1 10000 cycles/80 %/-A g À 1 [31] CoP//FeP 4 46 W h kg À 1 /695 W kg À 1 34 W h kg À 1 /7 kW kg À 1 10000 cycles/89 %/10 A g À 1 [32] This work 71 W h kg À 1 /890 W kg À 1 38 W hkg À 1 /7.9 kW kg À 1 10000cycles/61 %/7 A g À 1 -…”

Design and synthesis of a MnCo-MOF modified flexible 3D graphene sponge electrode for an asymmetric supercapacitor with high power and energy density

“…It was observed that MnCo-MOF/3DG//3DG has higher energy and power density compared to other graphene-based materials, which can be attributed to its battery-type performance and electroactive and porous MOF structures. 36,37,52–57 MnCo-MOF/3DG//3DG has the energy to keep the green light emitting diode (LED) lit for 10 min (Fig. 7c) and can emit light of high intensity even after 10 min (Fig.…”

“…11 Then, up to half of both MnCo-MOF/3DG and 3DG were immersed in this prepared polymer gel electrolyte for 1 h and dried at room temperature for 24 h after removal. 3DG materials coated on one side with PVA-KOH were sandwiched between the gel electrolyte parts, and a conductive and flexible graphene paper (GP) electrode 35,36 was placed on the outside as a current collector. Then, the ASC circuit was prepared by wrapping the outer parts with insulating tape so that the GP ends were exposed.…”