Low-cost H2/K+ hybrid batteries for large-scale energy storage

Rechargeable hydrogen gas batteries are gaining significant attention as a highly reliable electrochemical energy storage technology. However, the high costs of both cathode and anode limit their widespread applications. Here, we demonstrate a low-cost H 2 /K + hybrid battery using Fe–Mn-based Prussian white - K 2 · 74 Mn[Fe(CN) 6 ] 0.90 ·0.13H 2 O (KMF) as cathode and non-noble metal high entropy alloy (NNM-HEA) as anode. It demonstrates a high capacity of 146.1 mAh g −1 at 1 A g −1 with excellent rate performance and stability. Even with a ∼7-fold increase in active loading of the KMF cathode, the capacity of the H 2 /K + battery remains as high as 100.5 mAh g −1 . Furthermore, a low-cost H 2 /K + hybrid battery using our newly developed NNM-HEA based hydrogen catalytic anode is successfully fabricated, which shows an extended capacity with a retention of 90% after 1200 cycles. This work will pave the way for designing low-cost electrode materials for high-performance, large-scale energy storage hydrogen gas batteries.