Professors Yang Chuncheng and Researcher Zhang Hong from the College of Materials Science and Engineering, Jilin University, in collaboration with Professor Lu Ke from Anhui University, proposed a high-medium-entropy gradient design strategy to stabilize manganese-based high-entropy Prussian blue analogue cathodes, which drastically improves the capacity, rate capability and long-cycle stability of aqueous zinc-ion batteries. The relevant research outcome, titled Stabilizing manganese-based prussian blue analogs via high-medium-entropy gradient design for durable aqueous zinc-ion batteries, was published on January 1, 2026 in Acta Materialia, a top journal in materials science.
Aqueous zinc-ion batteries stand out as a promising candidate for large-scale energy storage owing to their high safety, abundant raw material reserves and low manufacturing cost. Prussian blue analogs feature an open three-dimensional framework that affords diffusion pathways for Zn²⁺ intercalation and deintercalation. Among them, manganese-based high-entropy Prussian blue analogs deliver elevated operating voltage and specific capacity through the Mn²⁺/Mn³⁺ redox couple. Nevertheless, the Mn redox reaction readily triggers Jahn–Teller distortion, which causes manganese dissolution, cleavage of Mn–N bonds and framework collapse, severely restricting their long-cycle practical application. To tackle this bottleneck, the research team integrated microfluidic confined crystallization with a coordination competition mechanism. By regulating the ordered release of metal ions and crystal growth within a millisecond-scale homogeneous mixing environment, a gradient core–shell architecture with an Mn-enriched high-entropy core and an Fe/Co/Ni/Cu medium-entropy shell was constructed. The high-entropy core weakens the degeneracy of Mn³⁺ eg orbitals via multi-metal d-orbital coupling, fundamentally suppressing Jahn–Teller distortion at the
source; meanwhile, the medium-entropy shell acts as an electrolyte barrier and stress buffer, mitigating direct exposure of Mn active sites and accelerating interfacial reaction kinetics.
In-situ XRD, in-situ Raman spectroscopy and XANES characterizations further elucidated the structural reversibility and charge compensation mechanism of the material during cycling. The HE-PBA-M cathode only undergoes slight lattice expansion upon charging, and its diffraction peaks nearly return to the original positions after discharge, demonstrating highly reversible structural evolution. Raman spectra verify the reversible variation of the Fe–C≡N–Mn coordination environment throughout charge/discharge cycles. XANES results confirm that Mn serves as the primary redox active center, Fe and Co participate in reversible valence fluctuation, while Cu and Ni mainly function as structural stabilizers.
Benefiting from the above synergistic design, the full cell assembled with the HE-PBA-M cathode achieves stable cycling over 6000 cycles at 0.5 A g⁻¹, with an ultralow average capacity decay rate of merely 0.004% per cycle.
Wang Peng, a postgraduate student of Jilin University, and Professor Wen Zi are the co-first authors of this paper. Professor Yang Chuncheng, Researcher Zhang Hong (Jilin University) and Professor Lu Ke (Anhui University) correspond to this work. This research was financially supported by the National Natural Science Foundation of China and the Science and Technology Development Program of Jilin Province.
