Chlorine-based batteries with Cl0 to Cl-redox reaction (CLRR) are expected to be used for high-performance energy storage due to their high redox potential and large theoretical capacity. However, the inherent gas-liquid conversion properties of CLRR, as well as poor CL fixation, can lead to Cl2 leakage, reduce battery reversibility, and raise safety concerns.
Here,Zhi Chunyi's team from City University of Hong KongUsing the selenium-based organic molecule diphenyl diselenide (Di-Ph-Se) as a CL anchoring agent, atomic-level CL fixation was achieved through chalco-halogen coordination chemistry, and a highly reversible CLRR with ultra-low Cl and significant discharge voltage (187 v vs zn2+/zn)。Two oxidized Cl0s anchored to a single pH-Se, as well as the multivalent conversion of Se, contribute to the six-electron conversion process, achieving a high discharge capacity of up to 507 mAh g-1 with an average voltage of 151 V, coulombic efficiency up to 993% with an energy density of up to 665 Wh kg-1.
Based on the excellent reversibility of the developed Di-Ph-SE electrode with CLRR, it exhibited excellent rate performance (205 mAh g-1 at 5 A g-1) and cycling performance (capacity retention of 77 after 500 cycles).3%)。It is worth noting that this pouch battery has up to 6The record area capacity and self-discharge performance of 87 mAh cm-2 demonstrate the great potential for real-world applications.
Figure 1Electrochemical performance of Zn-Di-Ph-SE cells with CLRR
In conclusion, this work uses double pH-Se as a Cl anchoring agent to achieve efficient Cl atom fixation with two Cl0 atoms anchored to one pH-Se. The resulting zn||The DI-PH-SE battery has an ideal six-electron conversion process, providing an impressive discharge voltage (up to 1.).51V) and discharge capacity (507 mAh g-1).
In addition, due to the stable molecular structure and electrolyte, extraordinary cycling performance is achieved, with a capacity retention rate of up to 77 after 500 cycles3%。zn||Di-PH-SE batteries have significant rate performance and high area capacity, low self-discharge rate, and a capacity retention rate of about 72 after 5 days of standing5%。Therefore, the use of sulfur-based anchoring agent design strategies opens up new avenues for the implementation of reversible halogen redox chemistry in batteries.
Figure 2To evaluate the stability and practicability of ZN-Di-PH-SE batteries
selenium-anchored chlorine redox chemistry in aqueous zinc dual-ion batteries，advanced materials2023 doi: 10.1002/adma.202309330