High‐Power Lithium‐Ion Capacitor using LiMnBO₃‐Nanobead Anode and Polyaniline‐Nanofiber Cathode with Excellent Cycle Life

Abstract

LiMnBO3 nanobeads (LMB-NB) with uniform size and distribution were synthesized using a urea-assisted microwave/solvothermal method. The potential application of LMB-NBs as an anode for a lithium-ion hybrid capacitor (Li-AHC) was tested with a polyaniline-nanofiber (PANI-NF) cathode in a nonaqueous LiPF6 (1 M)-ethylene carbonate/dimethyl carbonate electrolyte. Cyclic voltammetry (CV) and charge-discharge (C/DC) studies revealed that the PANI-NF/LMB-NB cell showed an exceptional capacitance behavior between 0-3 V along with a prolonged cycle life. A discharge capacitance of about 125 F g(-1) , and energy and power densities of about 42 Wh kg(-1) and 1500 W kg(-1) , respectively, could be obtained at a current density of 1 A g(-1) ; those Li-AHC values are higher relative to cells containing various lithium intercalation materials in nonaqueous electrolytes. In addition, the PANI-NF/LMB-NB cell also had an outstanding rate performance with a capacitance of 54 F g(-1) and a power density of 3250 W kg(-1) at a current density of 2.25 A g(-1) and maintained 94% of its initial value after 30000 cycles. This improved capacitive performance with an excellent electrochemical stability could be the result of the morphological features and inherent conductive nature of the electroactive species.

Pushing the Energy Output and Cyclability of Sodium Hybrid Capacitors at High Power to New Limits

“…The obtained capacitance is attributed only due to ClO 4 − adsorption, thereby eliminating the contribution from pseudocapacitance from functional groups which could reduce the cyclability of GNS electrodes . The obtained capacitance is one the highest ever achieved for an adsorption electrode, given that activated carbon‐type electrodes deliver a limited capacitance of around 65–80 F g −1 at this current density and fails at higher current density . GNS retained a high capacitance of ≈118, 107, 88, and 78 F g −1 at the corresponding current densities of 0.25, 0.5, 2, and 5 A g −1 (Figure c).…”

2D polyaniline with exchangeable interlayer fluid for fast and stable volumetric dual ion storage

“…6(d) with a capacity retention rate of 63.3% after 2000th cycle at a current density of 200 mA g À1 , while the value of PANi is only 39.7% under the same operational condition. The better stability of TALP could be due to the inherent conductive nature and the lower stress generated during charge/discharge with the 2D layered structure with confined electrolyte in comparison of PANi with twisted structure [35]. The electrochemical impedance spectroscopy (EIS) spectra of TALP(Electrolyte) and PANi electrode in a half-cell with Li metal as reference electrode were also recorded, which relate to the intrinsic resistance of active materials, charge-transfer resistance and ionic diffusion in different frequency regions [36,37].…”

Nanostructured Anode Materials for Non‐aqueous Lithium Ion Hybrid Capacitors

“…Typical insertion‐type metal oxides are compounds with a 3D network structure that can reversibly intercalate/deintercalate Li ion into/out of the host lattice. Insertion‐type electrodes, include Li 4 Ti 5 O 12 , TiO 2 (anatase, bronze), TiNb 2 O 7 , Nb 2 O 5 , Li 3 VO 4 , H 2 Ti 6 O 13 , LiMnBO 3 , etc., have been explored for LIHC applications . The volume change accompanying this Li intercalation process is comparatively small (nearly 0% for Li 4 Ti 5 O 12 and <4% for anatase TiO 2 ), which ensures the structural integrity of the host lattice and renders high coulombic efficiency and long cycling life …”