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A Self‐Supported λ‐MnO 2 Film Electrode used for Electrochemical Lithium Recovery from Brines
Author(s) -
Xu Xin,
Zhou You,
Feng Zhiwen,
Kahn Naeem Ullah,
Haq Khan Zia Ul,
Tang Yang,
Sun Yanzhi,
Wan Pingyu,
Chen Yongmei,
Fan Maohong
Publication year - 2018
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201800185
Subject(s) - spinel , electrode , materials science , lithium (medication) , electrochemistry , aqueous solution , cathode , chemical engineering , inorganic chemistry , chemistry , metallurgy , medicine , engineering , endocrinology
Lithium recovery from an aqueous resource was accelerated by electrochemically driving the transformation of Mn IV /Mn III with a spinel λ‐MnO 2 film electrode. A λ‐MnO 2 electrode without binders or conductive additives is preferred for achieving a large capacity at high current density and long‐term cycling capability. In this study, a film of Mn(OH) 2 was first deposited on the surface of Pt or graphite substrates owing to alkalization near the cathode, then it was oxidized to a Mn 3 O 4 film by air, followed by being hydrothermally lithiated to LiMn 2 O 4 spinel and, finally, it was turned into the λ‐MnO 2 film electrode through potentiostatic delithiation. The results show that the charging/discharging electric capacity of the fabricated λ‐MnO 2 film electrode was up to ≈100 mAh g −1 at a current density of 50 mA g −1 in 30 m m Li + aqueous solution, twice that of the λ‐MnO 2 powder electrode. Also, 82.3 % lithium capacity remained after 100 cycles of an electrochemically assisted lithium recovery process, indicating high availability and good stability of the λ‐MnO 2 spinel on the electrode. The energy consumption for each cycle is estimated to be approximately 1.55±0.09 J, implying that only 4.14 Wh is required for recovery of one mole of lithium ions by this method.