In:
ECS Meeting Abstracts, The Electrochemical Society, Vol. MA2016-03, No. 2 ( 2016-06-10), p. 133-133
Abstract:
Layered transition-metal oxides have served as the mainstream cathode materials for high-energy batteries due to their large theoretical capacity (≈280mAh/g),However, the actual usable capacity is much lower than the promised theoretical value. Additional, poor cycling performance and the first-cycle Coulombic efficiency, for which Mn(II)-dissolution, its immobilization in solid electrolyte interface (SEI), oxidation of electrolytes by Ni, and other parasitic process thereat have been held responsible, weight against their applications.. Here we report a significant enhancement of cathode capacity utilization through a novel concept of material design. By embedding Li(Ni 0.5 Co 0.2 Mn 0.3 )O 2 in single wall carbon nanotube (CNT) network, a high charge/discharge reversible capacity up to about 250 mAh/g was obtained between 3.0-4.8V. Furthermore, to maintain this high capacity in long-term cycling, we proposes a unique “pre-lithiation process”, which brought the cathode to low potentials before regular cycling and led to an interphase that is normally formed only on anode surfaces. The complete coverage of cathode surface by this ~40 nm-thick interphase effectively prevented Mn(II) dissolution and minimized the side reactions of Ni, Co and Mn at the NMC interface during the subsequent cycling process. More importantly, such “pre-lithiation” process activated a structure containing two Li layers near the surface of NMC532 particles, as verified by XRD and first principle calculation. Hence, a new cathode material of both high capacity with depolarized structure; and excellent cycling performance was generated.
Type of Medium:
Online Resource
ISSN:
2151-2043
DOI:
10.1149/MA2016-03/2/133
Language:
Unknown
Publisher:
The Electrochemical Society
Publication Date:
2016
detail.hit.zdb_id:
2438749-6
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