Electrochemical Performance of Citric Acid-Modified α-MnO2 Cathode for Aqueous Zinc-Ion Batteries
5 affiliations
- 1Hubei Key Laboratory of Low-Carbon and Safe Storage & Transportation of Oil, Gas and New Energy, Yangtze University, Wuhan 430100, China
- 2School of Petroleum Engineering, Yangtze University, Wuhan 430100, China
- 3State Key Laboratory of Low Carbon Catalysis and Carbon Dioxide Utilization, Yangtze University, Wuhan 430100, China
- 4Department of Physics and Semiconductor Science, Gachon University, Seongnam-si 13120, Gyeonggi-do, Republic of Korea
- 5Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, School of Energy Science and Technology, Liaocheng University, Liaocheng 252059, China
Abstract
Aqueous zinc-ion batteries (AZIBs) are considered promising for large-scale energy storage owing to their intrinsic safety, low cost, and environmental friendliness. α-MnO2, with its unique 2 × 2 tunnel structure, is regarded as one of the most promising cathode materials for zinc-ion batteries; however, its cycling stability is poor due to the disproportionation and dissolution of Mn3+ and structural collapse. In this work, α-MnO2 was prepared by a hydrothermal method with citric acid introduced into the precursor solution, yielding a MnO2@CA cathode material. Results show that the citric acid modification does not change the main crystal structure of α-MnO2, and SEM images reveal that both the pristine and modified samples present nanorod morphology. Electrochemical tests demonstrate that after 100 cycles at 0.5 A·g−1, the MnO2@CA electrode still retains a discharge-specific capacity of about 200 mAh·g−1 with a capacity retention of about 90%, while the pristine α-MnO2 electrode decays to about 75 mAh·g−1. At 0.1 and 0.2 A·g−1, MnO2@CA delivers higher specific capacities than pristine α-MnO2, and it also shows better capacity recovery after the current density returns to 0.1 A·g−1. At high rates, the rate performance is somewhat limited by solid-state diffusion/concentration polarization after low-rate activation, while the long-term cycling stability is significantly improved. Kinetics analysis indicates that the electrode process is dominated by diffusion control, while the capacitive contribution increases monotonically with scan rate (from about 7% to 19%) but remains minor compared with the diffusion contribution. Citric acid modification is proposed to stabilize Mn species through chelation, thereby suppressing Mn dissolution, and alleviating structural stress, thereby effectively enhancing the cycling stability and low-rate discharge capacity of the α-MnO2 cathode.
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BibTeX
@article{yu2026electrochemical,
title = {{Electrochemical Performance of Citric Acid-Modified α-MnO2 Cathode for Aqueous Zinc-Ion Batteries}},
author = {Huan Yu and Yutong Jia and Mingting Liu and Man Li and Xianghua Zhang and Weiwei Han},
journal = {International Journal of Molecular Sciences},
year = {2026},
month = nov,
doi = {10.3390/ijms27219857},
url = {https://www.mdpi.com/1422-0067/27/21/9857},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Electrochemical Performance of Citric Acid-Modified α-MnO2 Cathode for Aqueous Zinc-Ion Batteries
AU - Huan Yu
AU - Yutong Jia
AU - Mingting Liu
AU - Man Li
AU - Xianghua Zhang
AU - Weiwei Han
PY - 2026
DA - 2026/11/03
JO - International Journal of Molecular Sciences
DO - 10.3390/ijms27219857
UR - https://www.mdpi.com/1422-0067/27/21/9857
AB - Aqueous zinc-ion batteries (AZIBs) are considered promising for large-scale energy storage owing to their intrinsic safety, low cost, and environmental friendliness. α-MnO2, with its unique 2 × 2 tunnel structure, is regarded as one of the most promising cathode materials for zinc-ion batteries; however, its cycling stability is poor due to the disproportionation and dissolution of Mn3+ and structural collapse. In this work, α-MnO2 was prepared by a hydrothermal method with citric acid introduced into the precursor solution, yielding a MnO2@CA cathode material. Results show that the citric acid modification does not change the main crystal structure of α-MnO2, and SEM images reveal that both the pristine and modified samples present nanorod morphology. Electrochemical tests demonstrate that after 100 cycles at 0.5 A·g−1, the MnO2@CA electrode still retains a discharge-specific capacity of about 200 mAh·g−1 with a capacity retention of about 90%, while the pristine α-MnO2 electrode decays to about 75 mAh·g−1. At 0.1 and 0.2 A·g−1, MnO2@CA delivers higher specific capacities than pristine α-MnO2, and it also shows better capacity recovery after the current density returns to 0.1 A·g−1. At high rates, the rate performance is somewhat limited by solid-state diffusion/concentration polarization after low-rate activation, while the long-term cycling stability is significantly improved. Kinetics analysis indicates that the electrode process is dominated by diffusion control, while the capacitive contribution increases monotonically with scan rate (from about 7% to 19%) but remains minor compared with the diffusion contribution. Citric acid modification is proposed to stabilize Mn species through chelation, thereby suppressing Mn dissolution, and alleviating structural stress, thereby effectively enhancing the cycling stability and low-rate discharge capacity of the α-MnO2 cathode.
SN - 1422-0067
ER -