Complete Decomposition of Li₂CO₃ in Li–O₂ Batteries Using Ir/B₄C as Noncarbon-Based Oxygen Electrode

Abstract

Instability of carbon-based oxygen electrodes and incomplete decomposition of LiCO during charge process are critical barriers for rechargeable Li-O batteries. Here we report the complete decomposition of LiCO in Li-O batteries using the ultrafine iridium-decorated boron carbide (Ir/BC) nanocomposite as a noncarbon based oxygen electrode. The systematic investigation on charging the LiCO preloaded Ir/BC electrode in an ether-based electrolyte demonstrates that the Ir/BC electrode can decompose LiCO with an efficiency close to 100% at a voltage below 4.37 V. In contrast, the bare BC without Ir electrocatalyst can only decompose 4.7% of the preloaded LiCO. Theoretical analysis indicates that the high efficiency decomposition of LiCO can be attributed to the synergistic effects of Ir and BC. Ir has a high affinity for oxygen species, which could lower the energy barrier for electrochemical oxidation of LiCO. BC exhibits much higher chemical and electrochemical stability than carbon-based electrodes and high catalytic activity for Li-O reactions. A Li-O battery using Ir/BC as the oxygen electrode material shows highly enhanced cycling stability than those using the bare BC oxygen electrode. Further development of these stable oxygen-electrodes could accelerate practical applications of Li-O batteries.

Fabricating Ir/C Nanofiber Networks as Free‐Standing Air Cathodes for Rechargeable Li‐CO2 Batteries

“…As one of the most studied noble metals due to high physical/chemical stability, Ir has successfully been used as catalysts for oxygen evolution reaction (OER) and Li‐O 2 batteries . Especially, it has also been reported that iridium‐decorated boron carbide (Ir/B 4 C) could facilitate the decomposition of Li 2 CO 3 and efficiently lower the overpotential of Li‐O 2 batteries . Inspired by these results, we expected that with the help of Ir, the coulombic efficiency and cycling life would be improved for Li‐CO 2 batteries.…”

A Rechargeable Li‐CO2 Battery with a Gel Polymer Electrolyte

“…Ex situ X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were employed to investigate CNTs cathodes at different stages.As shown in Figure 3g,t he diffraction peaks after discharge indicates the formation of Li 2 CO 3 (PDF No.09-0359), and disappears on recharge subsequently in both GPE and liquid electrolyte.Itisapparent that the XRD pattern for characteristic peaks of Li 2 CO 3 formed in the GPE-based Li-CO 2 battery (Figure 3g,p ink line) is much broader and less intense than that in liquid electrolyte (Figure 3g,b lue line), indicating poor crystallinity.T his poorly crystalline Li 2 CO 3 possesses au nique particle-shaped morphology (Figure 3b), which has been shown to generate and decompose at relatively low discharge-charge overpotential in the Li-CO 2 battery (Figure 2c). [10,26,[30][31][32] However, the data of in situ DEMS cannot directly demonstrate the recovery of CO 2 because the undesired decomposition of electrolyte on charge may also leads to the release of CO 2 .For present case,t he in situ DEMS data coupled with the ex situ characterization (for example,X RD,F TIR, Raman) about charge-discharge products only indicate the preliminary conclusion of the recovery of CO 2 in the charging process. [18] Furthermore, al ot of investigations have confirmed that the formation of poorly crystalline (or amorphous) Li 2 O 2 can improve electrochemical performance of corresponding Li-O 2 cells.…”

Highly Graphitic Carbon Nanofibers Web as a Cathode Material for Lithium Oxygen Batteries

“…The XRD results of CNF electrodes in Figure 5a reveal the formation of lithium peroxide (Li2O2) without Li2O and LiOH [7,43]. The Li2Co3 of byproducts peak observed from XRD pattern [44,45]. In the Raman spectra (Figure 5b), the intensity ratios of the D-band to the G-band for CNF electrodes after 1 cycle increase significantly compared to those of pristine CNF electrodes.…”