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Im HJ, Park YJ. Interfacial Stabilization of Li 2O-Based Cathodes by Malonic-Acid-Functionalized Fullerenes as a Superoxo-Radical Scavenger for Suppressing Parasitic Reactions. ACS APPLIED MATERIALS & INTERFACES 2022; 14:38952-38962. [PMID: 35973056 DOI: 10.1021/acsami.2c11844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The utilization of an anionic redox reaction as an innovative strategy for overcoming the limitations of cathode capacity in lithium-ion batteries has recently been the focus of intensive research. Li2O-based materials using the anionic (oxygen) redox reaction have the potential to deliver a much higher capacity than commercial cathodes using cationic redox reactions based on transition-metal ions. However, parasitic reactions attributed to the superoxo species (such as LiO2), derived from the Li2O active material of the cathode, deteriorate the stability of the interface between the cathode and electrolyte, which has limited the commercialization of Li2O-based cathodes. To address this issue, malonic-acid-functionalized fullerenes (MC60) were applied in the electrolyte as an additive for scavenging the superoxo radicals (O21- in LiO2) that trigger parasitic reactions. MC60 can efficiently capture superoxo radicals using the π-conjugated surface and the malonate functionality on the surface. As a result, MC60 considerably enhanced the available capacity and cycling performance of the Li2O-based cathodes, decreased the interfacial layer formed on the cathode surface, and hindered the generation of byproducts, such as Li2CO3, CO2, and C-F3, derived from parasitic reactions. In addition, the loss of Li2O from the cathode surface during cycling was also suppressed, validating the ability of MC60 to capture superoxo radicals. This result confirms that the introduction of MC60 can effectively alleviate the parasitic reactions at the cathode/electrolyte interface and improve the electrochemical performance of Li2O-based cathodes by scavenging the superoxo species.
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Affiliation(s)
- Hee Jeong Im
- Department of Advanced Materials Engineering, Kyonggi University, 154-42, Gwanggyosan-Ro, Yeongtong-Gu, Suwon-Si, Gyeonggi-Do 16227, Republic of Korea
| | - Yong Joon Park
- Department of Advanced Materials Engineering, Kyonggi University, 154-42, Gwanggyosan-Ro, Yeongtong-Gu, Suwon-Si, Gyeonggi-Do 16227, Republic of Korea
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Hwang YY, Han JH, Park SH, Jung JE, Lee NK, Lee YJ. Understanding anion-redox reactions in cathode materials of lithium-ion batteries through in situcharacterization techniques: a review. NANOTECHNOLOGY 2022; 33:182003. [PMID: 35042200 DOI: 10.1088/1361-6528/ac4c60] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
As the demand for rechargeable lithium-ion batteries (LIBs) with higher energy density increases, the interest in lithium-rich oxide (LRO) with extraordinarily high capacities is surging. The capacity of LRO cathodes exceeds that of conventional layered oxides. This has been attributed to the redox contribution from both cations and anions, either sequentially or simultaneously. However, LROs with notable anion redox suffer from capacity loss and voltage decay during cycling. Therefore, a fundamental understanding of their electrochemical behaviors and related structural evolution is a prerequisite for the successful development of high-capacity LRO cathodes with anion redox activity. However, there is still controversy over their electrochemical behavior and principles of operation. In addition, complicated redox mechanisms and the lack of sufficient analytical tools render the basic study difficult. In this review, we aim to introduce theoretical insights into the anion redox mechanism andin situanalytical instruments that can be used to prove the mechanism and behavior of cathodes with anion redox activity. We summarized the anion redox phenomenon, suggested mechanisms, and discussed the history of development for anion redox in cathode materials of LIBs. Finally, we review the recent progress in identification of reaction mechanisms in LROs and validation of engineering strategies to improve cathode performance based on anion redox through various analytical tools, particularly,in situcharacterization techniques. Because unexpected phenomena may occur during cycling, it is crucial to study the kinetic properties of materialsin situunder operating conditions, especially for this newly investigated anion redox phenomenon. This review provides a comprehensive perspective on the future direction of studies on materials with anion redox activity.
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Affiliation(s)
- Ye Yeong Hwang
- Department of Energy Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Ji Hyun Han
- Department of Energy Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Sol Hui Park
- Department of Energy Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Ji Eun Jung
- Department of Energy Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Nam Kyeong Lee
- Department of Energy Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Yun Jung Lee
- Department of Energy Engineering, Hanyang University, Seoul 04763, Republic of Korea
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Interfacial reactions in lithia-based cathodes depending on the binder in the electrode and salt in the electrolyte. Sci Rep 2022; 12:527. [PMID: 35017583 PMCID: PMC8752660 DOI: 10.1038/s41598-021-04439-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/21/2021] [Indexed: 11/18/2022] Open
Abstract
Lithia (Li2O)-based cathodes, utilizing oxygen redox reactions for obtaining capacity, exhibit higher capacity than commercial cathodes. However, they are highly reactive owing to superoxides formed during charging, and they enable more active parasitic (side) reactions at the cathode/electrolyte and cathode/binder interfaces than conventional cathodes. This causes deterioration of the electrochemical performance limiting commercialization. To address these issues, the binder and salt for electrolyte were replaced in this study to reduce the side reaction of the cells containing lithia-based cathodes. The commercially used polyvinylidene fluoride (PVDF) binder and LiPF6 salt in the electrolyte easily generate such reactions, and the subsequent reaction between PVDF and LiOH (from decomposition of lithia) causes slurry gelation and agglomeration of particles in the electrode. Moreover, the fluoride ions from PVDF promote side reactions, and LiPF6 salt forms POF3 and HF, which cause side reactions owing to hydrolysis in organic solvents containing water. However, the polyacrylonitrile (PAN) binder and LiTFSI salt decrease these side reactions owing to their high stability with lithia-based cathode. Further, thickness of the interfacial layer was reduced, resulting in decreased impedance value of cells containing lithia-based cathodes. Consequently, for the same lithia-based cathodes, available capacity and cyclic performance were increased owing to the effects of PAN binder and LiTFSI salt in the electrolyte.
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Kobayashi H, Tsukasaki T, Ogasawara Y, Hibino M, Kudo T, Mizuno N, Honma I, Yamaguchi K. Cation-Disorder-Assisted Reversible Topotactic Phase Transition between Antifluorite and Rocksalt Toward High-Capacity Lithium-Ion Batteries. ACS APPLIED MATERIALS & INTERFACES 2020; 12:43605-43613. [PMID: 32886483 DOI: 10.1021/acsami.0c10768] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Multielectron reaction electrode materials using partial oxygen redox can be potentially used as cathodes in lithium-ion batteries, as they offer numerous advantages, including high reversible capacity and energy density and low cost. Here, a reversible three-electron reaction is demonstrated utilizing topotactic phase transition between antifluorite and rocksalt in a cation-disordered antifluorite-type cubic Li6CoO4 cathode. This cubic phase is synthesized by a simple mechanochemical treatment of conventionally prepared tetragonal Li6CoO4. It displays a reversible capacity of 487 mAh g-1, a high value because of a reversible three-electron reaction using Co2+/Co3+, Co3+/Co4+, and O2-/O22- redox, occurring without O2 gas evolution. The mechanochemical treatment is assumed to reduce its lattice distortion by cation-disordering and facilitate a reversible topotactic phase transition between antifluorite and rocksalt structures via a dynamic cation pushing mechanism.
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Affiliation(s)
- Hiroaki Kobayashi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Takashi Tsukasaki
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Yoshiyuki Ogasawara
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Mitsuhiro Hibino
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Tetsuichi Kudo
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Noritaka Mizuno
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Itaru Honma
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Kazuya Yamaguchi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
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