Operando calorimetry informs the origin of rapid rate performance in microwave-prepared TiNb2O7 electrodes

JOURNAL OF POWER SOURCES

卷:490

Article

Baek, Sun Woong¹  Wyckoff, Kira E.^2,3  Butts, Danielle M.⁴  Bienz, Jadon⁵  Likitchatchawankun, Ampol⁶  Preefer, Molleigh B.⁵  Frajnkovic, Matevz¹  Dunn, Bruce S.^4,7  Seshadri, Ram^2,3,5  Pilon, Laurent^1,7,8 

[1] Univ Calif Los Angeles, Henry Samueli Sch Engn & Appl Sci, Mech & Aerosp Engn Dept, Los Angeles, CA 90095 USA

[2] Univ Calif Santa Barbara, Mat Dept, Santa Barbara, CA 93106 USA

[3] Univ Calif Santa Barbara, Mat Res Lab, Santa Barbara, CA 93106 USA

[4] Univ Calif Los Angeles, Henry Samueli Sch Engn & Appl Sci, Dept Mat & Engn, Los Angeles, CA 90095 USA

[5] Univ Calif Santa Barbara, Dept Chem & Biochem, Santa Barbara, CA 93106 USA

[6] King Mongkuts Univ Technol North Bangkok KMUTNB, Sirindhom Int Thai German Grad Sch Engn TGGS, Mech Engn Simulat & Design Grp, 1518 Pracharat 1 Rd, Bangkok 10800, Thailand

[7] Univ Calif Los Angeles, Calif NanoSyst Inst, Los Angeles, CA 90095 USA

[8] Univ Calif Los Angeles, Inst Environm & Sustainabil, Los Angeles, CA 90095 USA

关键词: Lithium ion batteries;    Reversible heat generation;    Entropy;    Microwave synthesis;    Thermal signature;    Lithium diffusion;   

DOI  :  10.1016/j.jpowsour.2021.229537

来源: Elsevier

【 摘 要 】

The shear-phase compound TiNb2O7 has recently emerged as a safe and high-volumetric density replacement for graphite anodes in lithium ion batteries. An appealing feature of TiNb2O7 is that it retains capacity even at high cycling rates. Here, we demonstrate that phase pure and crystalline TiNb2O7 can be rapidly prepared using a high-temperature microwave synthesis method. Studies of the charging and discharging of this material, including through operando calorimetry, permit key thermodynamic parameters to be revealed. The nature of heat generation is dominated by Joule heating, which sensitively changes as the conductivity of the electrode increases with increasing lithiation. The enthalpy of mixing, obtained from operando calorimetry, is found to be small across the different degrees of lithiation, pointing to the high rate of lithium ion diffusion at the origin of rapid rate performance.

【 授权许可】

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