Ultrahigh-Loading Manganese-Based Electrodes for Aqueous Batteries via Polymorph Tuning

Xin Xiao; Zewen Zhang; Yecun Wu; Jinwei Xu; Xin Gao; Rong Xu; Wenxiao Huang; Yusheng Ye; Solomon T Oyakhire; Pu Zhang; Baoliang Chen; Emre Cevik; Sarah M Asiri; Ayhan Bozkurt; Khalil Amine; Yi Cui

doi:10.1002/adma.202211555

Ultrahigh-Loading Manganese-Based Electrodes for Aqueous Batteries via Polymorph Tuning

Adv Mater. 2023 Aug;35(33):e2211555. doi: 10.1002/adma.202211555. Epub 2023 Jul 6.

Authors

Xin Xiao¹, Zewen Zhang¹, Yecun Wu², Jinwei Xu¹, Xin Gao¹, Rong Xu¹, Wenxiao Huang¹, Yusheng Ye¹, Solomon T Oyakhire³, Pu Zhang¹, Baoliang Chen⁴, Emre Cevik⁵, Sarah M Asiri⁵, Ayhan Bozkurt⁵, Khalil Amine^{1

5

6}, Yi Cui^{1

7}

Affiliations

¹ Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA.
² Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA.
³ Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA.
⁴ Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
⁵ Bioenergy Research unit, Department of Biophysics, Institute for Research and Medical Consultations, Imam Abdulrahman Bin Faisal University, Dammam, 31441, Saudi Arabia.
⁶ Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL, 60439, USA.
⁷ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.

PMID: 37149287
DOI: 10.1002/adma.202211555

Abstract

Manganese-based aqueous batteries utilizing Mn²⁺ /MnO₂ redox reactions are promising choices for grid-scale energy storage due to their high theoretical specific capacity, high power capability, low-cost, and intrinsic safety with water-based electrolytes. However, the application of such systems is hindered by the insulating nature of deposited MnO₂ , resulting in low normalized areal loading (0.005-0.05 mAh cm^-2 ) during the charge/discharge cycle. In this work, the electrochemical performance of various MnO₂ polymorphs in Mn²⁺ /MnO₂ redox reactions is investigated, and ɛ-MnO₂ with low conductivity is determined to be the primary electrochemically deposited phase in normal acidic aqueous electrolyte. It is found that increasing the temperature can change the deposited phase from ɛ-MnO₂ with low conductivity to γ-MnO₂ with two order of magnitude increase in conductivity. It is demonstrated that the highly conductive γ-MnO₂ can be effectively exploited for ultrahigh areal loading electrode, and a normalized areal loading of 33 mAh cm^-2 is achieved. At a mild temperature of 50 °C, cells are cycled with an ultrahigh areal loading of 20 mAh cm^-2 (1-2 orders of magnitude higher than previous studies) for over 200 cycles with only 13% capacity loss.

Keywords: MnO2 polymorph; aqueous battery; electronic conductivity; gamma-MnO2; grid-scale energy storage.

Abstract

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