Robust lithium storage of block copolymer-templated mesoporous TiNb2O7 and TiNb2O7@C anodes evaluated in half-cell and full-battery configurations. (20th May 2021)

• Record Type: Journal Article
• Authors: Qian, Ruifeng; Yang, Chengfu; Ma, Dongwei; Li, Kaiming; Feng, Ting; Feng, Jijun; Pan, Jia Hong
• Is Part Of: Electrochimica acta. Volume 379(2021)
• Publication Date: 2021-05-20
• Subjects: Lithium-ion batteries -- TiNb2O7 -- Mesoporous materials -- Self-assembly -- Electrochemical energy storage; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2021.138179
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Mesoporous TiNb2 O7 ( m -TNO) is prepared by block copolymer-mediated evaporation induced self-assembly (EISA) process. m -TNO@C with surface carbon coating is synthesized by calcining m -TNO with glucose. m -TNO and m -TNO@C are successfully used as anode material of lithium-ion batteries with half-cell and full-battery configurations. Electrochemical properties of m -TNO and m -TNO@C systematically evaluated for practical applications. Abstract: We report a facile Pluronic F127-mediated evaporation-induced self-assembly (EISA) process for the scalable preparation of mesoporous TiNb2 O7 ( m -TNO) with an uniform grain size of ~12 nm. The elaborated m -TNO are demonstrated as an excellent anode material for lithium-ion batteries (LIBs) able to deliver a high discharge specific capacity of 235.7 mAh/g at 1 C and 109.2 mAh/g even at 20 C, with high capacity retention rate up to 94.6% after 100 cycles at 1 C in half cell. In addition, the m -TNO electrode delivers a specific capacity of 257.1 mAh/g at a current density of 0.5 C in the m -TNO/LiFePO4 full cell, and a high discharge capacity of 185.1 mAh/g can be achieved with a capacity retention rate of 78.7% even at 1 C after 800 cycles. To further improve the electrochemical performances, carbon-coated m -TNO ( m -TNO@C) is also synthesized by calcining the mixture of m -TNO and glucose. The initial discharge specific capacity of m -TNO@C is 248.4 mAh/g, and the capacity retention after 100 cycles at 1 C is 90.1%. The conductive carbon layer on m -TNO significantly improves the electronic conductivity of m -TNO. Cyclic voltammetry (CV) and electrical impedance spectroscopy (EIS) analyses show that coating the carbon layer by grinding will reduce the Li + ion diffusion rate and lower its rate performance under the high current density, compared with the uncoated counterpart. Both of m -TNO and m -TNO@C deliver long-term cyclic stability with the large capacity of ~160 mAh/g even at 5 C after 800 cycle, accompanied by the capacity retention rate of ~70%, exhibiting excellent electrochemical performances in LIBs.