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N7-(carboxymethyl)guanine-Lithium Crystalline Complex: A Bioinspired Solid Electrolyte.

Dutta D, Nagapradeep N, Zhu H, Forsyth M, Verma S, Bhattacharyya AJ - Sci Rep (2016)

Bottom Line: G7Li, with it's in-built supply of Li(+)-ions, exhibited remarkably high lithium-ion transference number (= 0.75) and tunable room temperature ionic conductivity spanning three decades (≈10(-7) to 10(-3) Ω(-1) cm(-1)) as a function of moisture content.The ionic conductivity show a distinct reversible transition around 80-100 °C, from a dual Li(+) and H(+) (<100 °C) to a pure Li(+) conductor (>100 °C).Systematic studies reveal a transition from water-assisted Li-ion transport to Li hopping-like mechanism involving guanine-Li coordination.

View Article: PubMed Central - PubMed

Affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore-560012 (Karnataka), India.

ABSTRACT
Electrochemical device with components having direct significance to biological life processes is a potent futuristic strategy for the realization of all-round green and sustainable development. We present here synthesis design, structural analysis and ion transport of a novel solid organic electrolyte (G7Li), a compound reminiscent of ion channels, derived from regioisomeric N7-guanine-carboxylate conjugate and Li-ions. G7Li, with it's in-built supply of Li(+)-ions, exhibited remarkably high lithium-ion transference number (= 0.75) and tunable room temperature ionic conductivity spanning three decades (≈10(-7) to 10(-3) Ω(-1) cm(-1)) as a function of moisture content. The ionic conductivity show a distinct reversible transition around 80-100 °C, from a dual Li(+) and H(+) (<100 °C) to a pure Li(+) conductor (>100 °C). Systematic studies reveal a transition from water-assisted Li-ion transport to Li hopping-like mechanism involving guanine-Li coordination. While as-synthesized G7Li has potential in humidity sensors, the anhydrous G7Li is attractive for rechargeable batteries.

No MeSH data available.


Related in: MedlinePlus

Arrhenius plot of the conductivity versus temperature(25–300 °C) of G7Li at 39% relative humidity(RH) (ambient condition).Inset: Nyquist plots for G7Li at25–300 °C temperatures. The equivalentcircuit for fitting the ac-impedance data is also shown.
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f4: Arrhenius plot of the conductivity versus temperature(25–300 °C) of G7Li at 39% relative humidity(RH) (ambient condition).Inset: Nyquist plots for G7Li at25–300 °C temperatures. The equivalentcircuit for fitting the ac-impedance data is also shown.

Mentions: The ionic conductivity of G7Li is estimated by ac-impedance spectroscopy (c/f ESI).Figure 4 shows the Arrhenius plot of ionic conductivityversus temperature (relative humidity, RH = 39%). Theimpedance data typically in the low conductivity regime comprised of a singlesemicircle. This data could be approximately fitted by a resistance (R1) andCPE1 (=Rn−1Cn)in parallel5678. In the high conductivity regime (i.e.(200–300) °C and around room temperature) theimpedance data comprised of a depressed semicircle and a“spike-like” region at high and low frequency regionrespectively. The impedance data in the high conductivity regimes are fitted to aseries combination in R1, 1 should be in normal mode and not suffix. It is writtenas R1 (R1) and constant phase element, CPE1 in parallel andCPE2 using ZViewTM software (Scribner Associates Inc.). The impedancedata, in general could be fitted well with n = 0.8resulting in bulk capacitance values ∼10−11F. Assuming the “spike-like” region to be another depressedsemicircle, reminiscent of ceramic conductors, fitting of the“spike-like” region is also attempted using a resistance(R2) in parallel to CPE2. In this case, the value of n whichfitted the data is found to be low (=0.5) which resulted in capacitance values∼10−6 F. As G7Li is not a ceramicconductor and hence does not possess well defined grain boundaries, it is stronglyfelt that this model here may not be appropriate. The impedance response of G7Li isvery similar to a soft-matter electrolyte such as polymer electrolyte with theadditional advantage of in-built lithium ions without the requirement of addition ofany external salts. As the aim here is to solely estimate the bulk contribution, theionic conductivities are estimated from resistance values as per the equivalentcircuit depicted in Fig. 4. The room temperature conductivityis found to be∼1.0 × 10−7 Ω−1 cm−1,which reduces to3.9 × 10−11 Ω−1 cm−1at 100 °C (Fig. 4). Interestingly, theconductivity increased sharply with further increase in temperature and reached avalue of0.2 × 10−5 Ω−1 cm−1at 300 °C. Upon cooling, the conductivity retraces its pathin both the temperature regimes i.e. 100–300 °Cand 25–100 °C about the point of minimum (c/fFigure S6). The conductivity (σ) in the100–300 °C temperature regime can be fitted tothe Arrhenius equation,σ = Aexp(−Ea/kT)where A is the pre-exponential factor, k the Boltzmann constant,T the absolute temperature and Ea being theactivation energy. The activation energy is estimated to be~0.8 eV in the temperature range100–300 °C (c/f Fig.4).


N7-(carboxymethyl)guanine-Lithium Crystalline Complex: A Bioinspired Solid Electrolyte.

Dutta D, Nagapradeep N, Zhu H, Forsyth M, Verma S, Bhattacharyya AJ - Sci Rep (2016)

Arrhenius plot of the conductivity versus temperature(25–300 °C) of G7Li at 39% relative humidity(RH) (ambient condition).Inset: Nyquist plots for G7Li at25–300 °C temperatures. The equivalentcircuit for fitting the ac-impedance data is also shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835778&req=5

f4: Arrhenius plot of the conductivity versus temperature(25–300 °C) of G7Li at 39% relative humidity(RH) (ambient condition).Inset: Nyquist plots for G7Li at25–300 °C temperatures. The equivalentcircuit for fitting the ac-impedance data is also shown.
Mentions: The ionic conductivity of G7Li is estimated by ac-impedance spectroscopy (c/f ESI).Figure 4 shows the Arrhenius plot of ionic conductivityversus temperature (relative humidity, RH = 39%). Theimpedance data typically in the low conductivity regime comprised of a singlesemicircle. This data could be approximately fitted by a resistance (R1) andCPE1 (=Rn−1Cn)in parallel5678. In the high conductivity regime (i.e.(200–300) °C and around room temperature) theimpedance data comprised of a depressed semicircle and a“spike-like” region at high and low frequency regionrespectively. The impedance data in the high conductivity regimes are fitted to aseries combination in R1, 1 should be in normal mode and not suffix. It is writtenas R1 (R1) and constant phase element, CPE1 in parallel andCPE2 using ZViewTM software (Scribner Associates Inc.). The impedancedata, in general could be fitted well with n = 0.8resulting in bulk capacitance values ∼10−11F. Assuming the “spike-like” region to be another depressedsemicircle, reminiscent of ceramic conductors, fitting of the“spike-like” region is also attempted using a resistance(R2) in parallel to CPE2. In this case, the value of n whichfitted the data is found to be low (=0.5) which resulted in capacitance values∼10−6 F. As G7Li is not a ceramicconductor and hence does not possess well defined grain boundaries, it is stronglyfelt that this model here may not be appropriate. The impedance response of G7Li isvery similar to a soft-matter electrolyte such as polymer electrolyte with theadditional advantage of in-built lithium ions without the requirement of addition ofany external salts. As the aim here is to solely estimate the bulk contribution, theionic conductivities are estimated from resistance values as per the equivalentcircuit depicted in Fig. 4. The room temperature conductivityis found to be∼1.0 × 10−7 Ω−1 cm−1,which reduces to3.9 × 10−11 Ω−1 cm−1at 100 °C (Fig. 4). Interestingly, theconductivity increased sharply with further increase in temperature and reached avalue of0.2 × 10−5 Ω−1 cm−1at 300 °C. Upon cooling, the conductivity retraces its pathin both the temperature regimes i.e. 100–300 °Cand 25–100 °C about the point of minimum (c/fFigure S6). The conductivity (σ) in the100–300 °C temperature regime can be fitted tothe Arrhenius equation,σ = Aexp(−Ea/kT)where A is the pre-exponential factor, k the Boltzmann constant,T the absolute temperature and Ea being theactivation energy. The activation energy is estimated to be~0.8 eV in the temperature range100–300 °C (c/f Fig.4).

Bottom Line: G7Li, with it's in-built supply of Li(+)-ions, exhibited remarkably high lithium-ion transference number (= 0.75) and tunable room temperature ionic conductivity spanning three decades (≈10(-7) to 10(-3) Ω(-1) cm(-1)) as a function of moisture content.The ionic conductivity show a distinct reversible transition around 80-100 °C, from a dual Li(+) and H(+) (<100 °C) to a pure Li(+) conductor (>100 °C).Systematic studies reveal a transition from water-assisted Li-ion transport to Li hopping-like mechanism involving guanine-Li coordination.

View Article: PubMed Central - PubMed

Affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore-560012 (Karnataka), India.

ABSTRACT
Electrochemical device with components having direct significance to biological life processes is a potent futuristic strategy for the realization of all-round green and sustainable development. We present here synthesis design, structural analysis and ion transport of a novel solid organic electrolyte (G7Li), a compound reminiscent of ion channels, derived from regioisomeric N7-guanine-carboxylate conjugate and Li-ions. G7Li, with it's in-built supply of Li(+)-ions, exhibited remarkably high lithium-ion transference number (= 0.75) and tunable room temperature ionic conductivity spanning three decades (≈10(-7) to 10(-3) Ω(-1) cm(-1)) as a function of moisture content. The ionic conductivity show a distinct reversible transition around 80-100 °C, from a dual Li(+) and H(+) (<100 °C) to a pure Li(+) conductor (>100 °C). Systematic studies reveal a transition from water-assisted Li-ion transport to Li hopping-like mechanism involving guanine-Li coordination. While as-synthesized G7Li has potential in humidity sensors, the anhydrous G7Li is attractive for rechargeable batteries.

No MeSH data available.


Related in: MedlinePlus