Surface Gradient Ti-Doped MnO₂ Nanowires for High-Rate and Long-Life Lithium Battery

Journal Article · Thu Nov 29 00:00:00 EST 2018 · ACS Applied Materials and Interfaces

DOI:https://doi.org/10.1021/acsami.8b13376· OSTI ID:1494397

Zhao, Kangning  ^[1]; Sun, Congli ^[2]; Yu, Yanhao  ^[3]; Dong, Yifan  ^[4]; Zhang, Chenyu ^[3]; Wang, Chongmin  ^[5]; Voyles, Paul M.  ^[3]; Mai, Liqiang  ^[4]; Wang, Xudong  ^[3]

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1. Department of Material Science and Engineering, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States; State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, P. R. China
2. Department of Material Science and Engineering, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States; Environmental and Molecular Sciences Laboratory (EMSL), Pacific Northwest National Laboratory, Richland 99352, Washington, United States
3. Department of Material Science and Engineering, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
4. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, P. R. China
5. Environmental and Molecular Sciences Laboratory (EMSL), Pacific Northwest National Laboratory, Richland 99352, Washington, United States

Cryptomelane-type a-MnO₂ has been demonstrated as a promising anode material for high-energy Li-ion batteries (LIBs) due to its high capacity and intriguing [2 × 2] tunnel structure. However, applications of MnO₂ electrode especially at high current rates and mass active material loading are limited by the poor mechanical stability, unstable solid electrolyte interphase (SEI) layer, and low reversibility of conversion reactions. Here, we report a design of homogeneous core-shell MnO₂ nanowires (NWs) created by near-surface gradient Ti doping (Ti-MnO₂ NWs). Such a structurally-coherent core-shell configuration endowed gradient volume expansion from inner core to outer shell, which could effectively release the stress of the NW lattice during the cycling and avoid the pulverization of the electrode. In this way, the Ti-MnO₂ NWs achieved a high reversible capacity (766 mAh g^-1 at 200 mA g^-1), a superior round-trip efficiency (coulombic efficiency achieved above 99.5% after only 30 cycles), and a long lifetime (a capacity of 742 mAh g^-1 after 3000 cycle at 10 A g^-1). In addition, the detailed conversion reaction mechanism was investigated through in-situ TEM, which further evidenced the unique homogeneous core-shell structure could largely suppress the separation of core and shell upon charging and discharging. This new NW configuration could benefit the design of other large-volume-change lithium battery anode materials.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1494397
• Report Number(s): PNNL-SA-132890
• Journal Information: ACS Applied Materials and Interfaces, Vol. 10, Issue 51; ISSN 1944-8244
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English