Joint
Enhancement in the Electrochemical Reversibility
and Cycle Lives for Copper Sulfide for Sodium- and Potassium-Ion Storage via Selenium Substitution
posted on 2021-12-01, 17:03authored byHezhe Lin, Jingyi Liu, Malin Li, Nan Chen, Wei Xuan, Lina Liu, Shiyu Yao, Fei Du
Transition
metal sulfides have received considerable interest as
the anodes for sodium-ion (SIBs) and potassium-ion batteries (PIBs)
owing to their high theoretical capacity and suitable working potential.
However, they suffer from poor electrochemical reversibility and limited
cycle lives. Herein, we design and synthesize a Se-substituted CuS
material, which demonstrates superior electrochemical properties for
both potassium and sodium storage because of the enhanced electronic
conductivity, lowered diffusion barrier, and shortened diffusion pathway.
The anode delivers a specific capacity of 374 mA h g–1 at a current density of 5 A g–1 in SIBs and 341
mA h g–1 at 2 A g–1 in PIBs and
nearly 100% capacity retention over 2000 cycles (SIBs) and 600 cycles
(PIBs), respectively. Moreover, a combined measurement including X-ray
diffraction, Raman, and transmission electron microscopy reveals an
interesting discharge product of Na2S0.8Se0.2, which could accelerate the conversion reaction and enhance
the electrochemical reversibility.