Metal–Organic Framework (MOF) Derived Electrodes with Robust and Fast Lithium Storage for Li‐Ion Hybrid Capacitors

Abstract

Hybrid metal-organic frameworks (MOFs) demonstrate great promise as ideal electrode materials for energy-related applications. Herein, a wellorganized interleaved composite of graphene-like nanosheets embedded with MnO 2 nanoparticles (MnO 2 @C-NS) using a manganese-based MOF and employed as a promising anode material for Li-ion hybrid capacitor (LIHC) is engineered. This unique hybrid architecture shows intriguing electrochemical properties including high reversible specific capacity 1054 mAh g −1 (close to the theoretical capacity of MnO 2 , 1232 mAh g −1 ) at 0.1 A g −1 with remarkable rate capability and cyclic stability (90% over 1000 cycles). Such a remarkable performance may be assigned to the hierarchical porous ultrathin carbon nanosheets and tightly attached MnO 2 nanoparticles, which provide structural stability and low contact resistance during repetitive lithiation/delithiation processes. Moreover, a novel LIHC is assembled using a MnO 2 @C-NS anode and MOF derived ultrathin nanoporous carbon nanosheets (derived from other potassium-based MOFs) cathode materials. The LIHC full-cell delivers an ultrahigh specific energy of 166 Wh kg −1 at 550 W kg −1 and maintained to 49.2 Wh kg −1 even at high specific power of 3.5 kW kg −1 as well as long cycling stability (91% over 5000 cycles). This work opens new opportunities for designing advanced MOF derived electrodes for next-generation energy storage devices.and power density as well as long cycle life at low cost. [1][2][3][4] In this context, a new system called "lithium-ion capacitors (LICs)" is proposed in the beginning of 21st century, which is hybrid arrangement of a battery-like (as anode) and supercapacitor-like electrodes (as cathode) in organic electrolyte, heading to enhance energy and power densities. [5][6][7] It has been emphasized that LIC bridges the low energy density supercapacitors (SCs) and low power Li-ion batteries (LIBs). [8,9] Such an excellent performance of LIC in terms of energy and power density is assigned to the coupling effect from the rapid charging rate of capacitor-type electrode, the large specific capacity of the battery-like electrode, and the much wider working potential window of the organic electrolytes. [5,6] So far, several hybrid LIC designs have been realized, which are based on an activated carbon (AC) cathode combined with graphite, Li 4 Ti 5 O 12 (LTO), vanadates (Li 3 VO 4 , BiVO 4 , etc.), or metal oxides anodes. [10][11][12][13][14][15][16] However, the poor rate capability of graphite, the relatively high redox potential (≈1.5 V, vs Li/Li + ) of LTO, the poor electrical conductivity, and the cycle stability of metal oxides hamper their utilization in high performance LICs. Therefore, it is crucial to explore the novel anode and cathode materials with high rate capability, good cycle stability, and low redox potential to achieve further improvements for hybrid LICs.

MoS2/carbon composites prepared by ball-milling and pyrolysis for the high-rate and stable anode of lithium ion capacitors

“…17 However, on account of the different mechanisms of energy storage, the power and energy densities depends on the faradaic-type anode with sluggish reaction kinetics and the adsorption-type cathode with low capacity, respectively. 18,19 It is an urgent and everlasting goal to construct an anode with high rate performance and long cycle life so that the whole device can deliver better performance by remedying the mismatch of kinetics and capacity between the cathode and anode.…”

Zinc Sulfide Decorated on Nitrogen‐Doped Carbon Derived from Metal‐Organic Framework Composites for Highly Reversible Lithium‐Ion Battery Anode

“…The insets of Figure a–d are the pore distribution of samples, which can determine the type of porous structure. The pore diameters of ZnS, ZnS@ZIF8, ZnS@C and ZnS@NC are 3.87, 2.31, 8.43, and 5.12, respectively, which mainly belong to mesoporous structure, facilitating the migration and diffusion of lithium ions …”

Functionalized Cu‐MOF@CNT Hybrid: Synthesis, Crystal Structure and Applicability in Supercapacitors

“…Owing to increase in engineering of commercial compact electronic devices, the demand for high energy storage in miniature form has increased enormously . In this regard, the electrochemical storage device such as supercapacitors are the most prominent candidate for highly efficient energy storage applications compared to fuel cell and lithium‐ion batteries, because of its high columbic efficiency, quick charge‐discharge process, outstanding environment friendliness, excellent cycling stability and reversibility, which can fulfill the demand for energy consumption and makes them superior to batteries having ordinary power density and cycle life span.…”