Pseudocapacitance‐Enhanced High‐Rate Lithium Storage in “Honeycomb”‐like Mn₂O₃ Anodes

Abstract

The realization of high‐power lithium‐ion batteries (LIBs) is heavily hampered by intrinsically slow lithium diffusion within solid electrodes. Capacitive‐like lithium storage behavior observed in transition‐metal oxide (TMO)‐based anodes shed light on attaining battery‐like capacity and supercapacitor‐like rate performance simultaneously. Herein, “honeycomb”‐like Mn2O3 films were successfully demonstrated as anodes for LIBs, in which the pseudocapacitive effect is strengthened upon cycling, resulting in a high‐rate lithium storage capability. Such pseudocapacitance originates from the unique porous structure and cycle‐induced microstructure evolution. The reticular Mn2O3 can reach 1584.9 mAh g−1 over 250 cycles at 1 A g−1, 1564.9 mAh g−1 after 500 cycles at 5 A −1, and 475.6 mAh g−1 at 15 A g−1.

Hierarchical Hollow‐Nanocube Ni−Co Skeleton@MoO3/MoS2 Hybrids for Improved‐Performance Lithium‐Ion Batteries

“…Additionally,ahigh specific surfacea rea of the nanostructured materials could form multiple SEI layers,which retarded electrolyte permeation and accelerated decompositiono ft he electrolyte. [28,35,52,[55][56][57] 3) The Li x MoS 2 intermediate phase, with metallicf eatures, could hugelyb oost the reaction kinetics. The dramatici ncrease in specific capacity may mainly be attributed to the following reasons:1 )Electrochemical delamination of the layered structure and expansion of the interlayers pacing decreased the diffusion resistanceo fl ithium ions.…”

“…[51] 2) The overcapacity may greatlyd erive from the fast kinetics of NCM-NCs. [28,35,52,[55][56][57] 3) The Li x MoS 2 intermediate phase, with metallicf eatures, could hugelyb oost the reaction kinetics. [42] 4) The crystal structure of NCM-NC hybridsi ss ignificantly improved, and the interlayer spacingo ft he MoS 2 phase Furthermore,t he NCM-NC electrode shows ah igh discharge specific capacity of 1178.4 mAh g À1 after 320 cycles under 1.0 Ag À1 .I nitial Coulombic efficiencies of NCM-NCs are 67.8, 67.2, 64.4, and 60.4 %a t0 .2, 1, 2, and 5Ag À1 ,r espectively.B ecause there is higher mechanical stress at higherc urrentd ensity and the formation of the metal phase and Li 2 Oc omposites is accelerated, [48] the NCM-NC electrodes have slight differences in reactivation time at different current densities (Figure 6d).…”

“…[13,36] The value of b was defined by the slope of plots of log (i)v ersus log (v). [35,[55][56][57] Moreover,t he proportion of the capacitive contribution can be obtained from Equations (17) and ( 18): [15,55] i ðVÞ¼k 1 vþk 2 v 1=2 ð17Þ It is worth mentioningt hat the value of b provides the basis for determining the energystoragem echanism of electrodes.…”

“…[13,15] The capacitive contribution (pink region in Figure 8c)i s8 8.2 %a t 1.0 mV s À1 ;t he remaining region belongs to the diffusion-controlled portion (Figure 8c). [35,[55][56][57] Therefore, electrochemical reactions of the NCM-NC electrodes are dominated by the capacitiveb ehavior,w hich implies that the NCM-NC hybridsp ossess fast electrochemical kinetics.…”

A Simple and Low‐Cost Method to Synthesize Cr‐Doped α‐Fe2O3 Electrode Materials for Lithium‐Ion Batteries

“…Furthermore, the results of the cycle performance reveal that the capacity initially decreased and then increased. This phenomenon may be due to the reversible growth of the polymer layer on the surface of the active material and the surface pseudocapacitive reaction ,. To further comprehend the excellent cycle stability for the FCF electrode, the morphologies of FCF and UF after 100 cycles at 0.5 A g −1 are explored.…”