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Greatly enhanced energy density of all‐solid‐state rechargeable battery operating in high humidity environments
Author(s) -
Wang Yuchen,
Akin Mert,
Qiao Xiaoyao,
Yan Zhiwei,
Zhou Xiangyang
Publication year - 2021
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.6928
Subject(s) - electrolyte , battery (electricity) , chemistry , ionic conductivity , analytical chemistry (journal) , relative humidity , anode , materials science , electrochemistry , electrochemical window , chemical engineering , electrode , thermodynamics , organic chemistry , power (physics) , physics , engineering
Summary Rubidium silver iodide (RbAg 4 I 5 ) owing to its unprecedented ionic conductivity (>0.2 S cm −1 at room temperature) and high stability in a wide temperature range (0°C‐100°C) is an ideal candidate for being used as an electrolyte material in solid‐state batteries. Our previous study showed that the exchange current density at the Ag/RbAg 4 I 5 anode and graphite/RbAg 4 I 5 cathode interfaces increased by three orders of magnitude when the environmental relative humidity (RH) increased from 35% to 100%. This prompted us to develop an all‐solid‐state battery that can operate in a wide RH range with exceptional stability. Here, we presented a novel rechargeable all‐solid‐state battery employing RbAg 4 I 5 solid electrolyte and Ag and graphite adhesive electrodes with the configuration of Ag, RbAg 4 I 5 /RbAg 4 I 5 /C, and RbAg 4 I 5 . Benefiting from the outstanding ionic conductivity of the solid electrolyte, the high electrochemical kinetics at high RH, a good interface between the RbAg 4 I 5 solid electrolyte and Ag and graphite adhesive electrodes, the all‐solid‐state battery exhibited excellent performance with a high energy density (153 Wh L −1 at 0.5 C) when exposed to an ambient environment with RH of 82%. Galvanostatic charge/discharge measurements also showed that the discharge capacity of the all‐solid‐state battery obtained in dry nitrogen (RH ~10%) and oxygen environments (RH ~10%) could be increased by more than 10‐folds in humid ambient air (RH ~80%), while the highest capacity was achieved under humidified argon environment (RH ~100%). The all‐solid‐state battery demonstrated excellent cyclic stability at 0.5 C with a capacity increase up to 2000 cycles due to the activation of the solid electrolyte and no capacity fade after 3500 cycles, whereas the capacity retention at 1.3 C was 36% after 1000 cycles. Our results unveiled that by the annealing process at 150°C for 12 hours, the charge/discharge capacity could be fully recovered. Electrochemical impedance spectroscopy and X‐ray diffraction analyses suggested that the reduction of charge capacity upon cycling at 1.3 C was due to an incomplete reversing of the electrochemical reaction at the anode, leading to a phase change from RbAg 4 I 5 to Rb 2 AgI 3 and β‐AgI. Nevertheless, annealing at 150°C converted Rb 2 AgI 3 and β‐AgI back into RbAg 4 I 5 . With the elimination of moisture‐proof packaging and reduced complexity of fabrication as well as the opportunity of miniaturization, the all‐solid‐state battery holds great potentials for special applications such as reserve battery, power systems in space, and energy storage in electronics, which require high reliability, a high degree of safety, prolonged shelf‐time, and ease of miniaturization.