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New Insight into the Confinement Effect of Microporous Carbon in Li/Se Battery Chemistry: A Cathode with Enhanced Conductivity
Author(s) -
Wang Xiwen,
Tan Yuqing,
Liu Zhixiao,
Fan Yuqin,
Li Mingnan,
Younus Hussein A.,
Duan Junfei,
Deng Huiqiu,
Zhang Shiguo
Publication year - 2020
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.202000266
Subject(s) - microporous material , cathode , electrolyte , electrochemistry , materials science , chemical engineering , carbon fibers , battery (electricity) , inorganic chemistry , nanotechnology , electrode , chemistry , composite material , power (physics) , physics , quantum mechanics , composite number , engineering
Abstract Embedding the fragmented selenium into the micropores of carbon host has been regarded as an effective strategy to change the Li–Se chemistry by a solid–solid mechanism, thereby enabling an excellent cycling stability in Li–Se batteries using carbonate electrolyte. However, the effect of spatial confinement by micropores in the electrochemical behavior of carbon/selenium materials remains ambiguous. A comparative study of using both microporous (MiC) and mesoporous carbons (MeC) with narrow pore size distribution as selenium hosts is herein reported. Systematic investigations reveal that the high Se utilization rate and better electrode kinetics of MiC/Se cathode than MeC/Se cathode may originate from both its improved Li+ and electronic conductivities. The small pore size (<1.35 nm) of the carbon matrices not only facilitates the formation of a compact and robust solid‐electrolyte interface (SEI) with low interfacial resistance on cathode, but also alters the insulating nature of Li 2 Se due to the emergence of itinerant electrons. By comparing the electrochemical behavior of MiC/Se cathode and the matching relationship between the diameter of pores and the dimension of solvent molecules in carbonate, ether, and solvate ionic liquid electrolyte, the key role of SEI film in the operation of C/Se cathode by quasi‐solid‐solid mechanism is also highlighted.