Aqueous secondary batteries are attracting increasing attention for their safety, cost and environmental benefits. However, their large-scale adoption faces obstacles due to a narrow electrochemical stability window and relatively low energy density. How can these limitations be overcome to fully exploit the potential of aqueous batteries in the field of energy storage?
Aqueous batteries have been recognized for their inherent safety, lower cost and lower ecological impact, positioning them as serious candidates for next-generation energy storage systems. However, their practical use is limited by a narrow electrochemical stability window and insufficient energy density, which restricts their performance and scalability in large-scale applications. These challenges highlight the need to develop advanced electrolytes capable of overcoming these barriers.
A major innovation in hydrogel electrolyte
In December 2024, researchers from China University of Petroleum (East China) revealed their findings in the journal Energy Materials and Devices. They synthesized a new hydrogel electrolyte, called Zn–SA–PSN, which, when combined with a Prussian blue cathode, achieves high energy density and cycle rate in sodium-zinc hybrid batteries. .
This hydrogel electrolyte is based on a unique polymer network characterized by interconnected amide chains and hydrophilic functional groups, key elements of its high performance. It offers an impressive ionic conductivity of 43 mS cm⁻¹, far exceeding traditional electrolytes, and an electrochemical stability window expanded to 2.5 V. This expansion allows operations at higher voltages, essential for improving energy density batteries.
Performance and potential applications
Working together with a Prussian blue cathode, the sodium-zinc hybrid battery shows remarkable performance, with over 6000 cycles and a minimum capacity degradation of only 0.0096% per cycle at a high current density of 25 C. This stability arises from the hydrogel electrolyte’s ability to suppress side reactions and inhibit dendrite growth, a common challenge with zinc anodes. Additionally, the battery achieves an energy density of approximately 220 Wh·kg⁻¹ with exceptional rate performance, up to 5 C. The versatility of the Zn–SA–PSN electrolyte allows its use with different materials cathodic, making its application compatible in aqueous sodium-zinc hybrid batteries and zinc ion batteries.
This innovation addresses critical limitations of current battery technologies and opens new avenues for future development. Indeed, Dr. Linjie Zhi, principal researcher, clarified: “Our hydrogel electrolyte represents a significant advancement in the field of aqueous batteries. Its ability to maintain high performance over thousands of cycles and at high current densities demonstrates its potential for practical applications in energy storage.»
-The development of Zn–SA–PSN hydrogel electrolyte has profound implications for the energy storage industry. Its ability to provide high energy density and long-term stability could transform battery systems for grid-scale energy storage, electric vehicles and other applications requiring efficiency and safety. This progress also highlights the potential of hybrid ion batteries to meet the growing demand for sustainable and efficient energy storage solutions.
Illustration caption: Gen AI
Article : ‘Advanced high-voltage and super-stable sodium–zinc hybrid ion batteries enabled by a hydrogel electrolyte’ – DOI : 10.26599/EMD.2024.9370050
Tsinghua University Press – Publication in the journal Energy Materials and Devices
