Trapping Lithium Selenides with Evolving Heterogeneous Interfaces for High-Power Lithium-Ion Capacitors

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Transition metal selenides offer fast kinetics and high capacity for Li-ion capacitors.
• Dissolution and shuttle of lithium selenides are significant challenges, hindering performance.

Purpose of the Study:

• To design and synthesize a heterostructure material to overcome lithium selenide dissolution and shuttle issues.
• To enhance the stability and cycling performance of transition metal selenide anodes.

Main Methods:

• Density functional theory calculations guided the design of heterogeneous structures.
• A CoSnO₃-MOF precursor was used to synthesize the CoSe₂/SnSe heterostructure.
• In situ X-ray diffraction (XRD) and disassembly experiments were employed to study interfacial evolution.

Main Results:

• The CoSe₂/SnSe heterostructure exhibited continuous evolution (CoSe₂/SnSe→Co/Sn→Co/Li₁₃ Sn₅).
• Achieved an ultrahigh reversible specific capacity of 510 mAh g^-1 after 1000 cycles at 4 A g^-1.
• In situ studies confirmed the inhibition of Li₂ Se shuttle by the evolving interface.

Conclusions:

• Heterogeneous structures enhance Li₂ Se adsorption, mitigating dissolution and shuttle effects.
• The continuously evolving interface in CoSe₂/SnSe provides a stable and high-performance anode material.
• This approach offers a promising strategy for Li-Se, Li-S batteries, and metal sulfide energy storage systems.