LiFePO₄ Particles Embedded in Fast Bifunctional Conductor rGO&C@Li₃V₂(PO₄)₃ Nanosheets as Cathodes for High‐Performance Li‐Ion Hybrid Capacitors

Abstract

The sluggish kinetics of Faradaic reactions in bulk electrodes is a significant obstacle to achieve high energy and power density in energy storage devices. Herein, a composite of LiFePO 4 particles trapped in fast bifunctional conductor rGO&C@Li 3 V 2 (PO 4 ) 3 nanosheets is prepared through an in situ competitive redox reaction. The composite exhibits extraordinary rate capability (71 mAh g −1 at 15 A g −1 ) and remarkable cycling stability (0.03% decay per cycle over 1000 cycles at 10 A g −1 ). Improved extrinsic pseudocapacitive contribution is the origin of fast kinetics, which endows this composite with high energy and power density, since the unique 2D nanosheets and embedded ultrafine LiFePO 4 nanoparticles can shorten the ion and electron diffusion length. Even applied to Li-ion hybrid capacitors, the obtained devices still achieve high power density of 3.36 kW kg −1 along with high energy density up to 77.8 Wh kg −1 . Density functional theory computations also validate that the remarkable rate performance is facilitated by the desirable ionic and electronic conductivity of the composite.

Post-annealing tailored 3D cross-linked TiNb2O7 nanorod electrode: towards superior lithium storage for flexible lithium-ion capacitors

“…They have attracted intensive research interest in the past two decades due to their merits such as increased energy density and working voltage compared with supercapacitors (SCs) based on activated carbons, and much better cycling stability and rate capability compared with Li-ion batteries. Nevertheless, the high-rate capability and power density of LICs are limited by the sluggish electrochemical kinetics of electrode materials used in traditional Li-ion batteries [4][5][6][7]. To address this issue, electrode materials of batteries are usually prepared in nanoscale, which significantly improves their high-rate performance due to dramatically shortened Li-ion diffusion path in nanosized particles [4][5][6][7][8][9].…”

“…Nevertheless, the high-rate capability and power density of LICs are limited by the sluggish electrochemical kinetics of electrode materials used in traditional Li-ion batteries [4][5][6][7]. To address this issue, electrode materials of batteries are usually prepared in nanoscale, which significantly improves their high-rate performance due to dramatically shortened Li-ion diffusion path in nanosized particles [4][5][6][7][8][9]. Recently, many efforts on LICs have been directed to the development of battery materials with specific nanostructures, especially high-potential anode materials [10][11][12].…”

Dendrite-structured FeF2 consisting of closely linked nanoparticles as cathode for high-performance lithium-ion capacitors

“…The energy bands at~724.8 and 711.3 eV (Fig. 2(h)) correspond well with the characteristic Fe 2p 1/2 and Fe 2p 3/2 , respectively, which are the characteristic features of Fe 2+ [19,38]. The XPS spectra of the F 1s region (Fig.…”

“…Although lithium-ion batteries (LIBs) and supercapacitors (SCs) are highly important electrochemical energy storage devices [14][15][16], in several ways, their capabilities are insufficient for the rapid development of modern society [17,18]. Recently, intense attention has been focused on lithium-ion capacitors (LICs) that are emerging hybrid energy storage devices that integrate the comprehensive advantages of both LIBs and SCs, serving as a bridge between these two technologies [2,[19][20][21]. It was found that LICs possess higher power density and higher energy density than the LIBs and SCs, respectively.…”

The Advance and Perspective on Electrode Materials for Metal–Ion Hybrid Capacitors

“…Compared with the performance of supercapacitor, battery shows a low power density because the chemical reactions occur within the electrode material. [ 7–40 ] Considering these limitations, research focus has been desperately put on the metal‐ion hybrid capacitor (MHC) combining the merits of battery and supercapacitor. The setup of MHC is composed of capacitor‐type and battery‐type electrode materials.…”