Element Screening of High-Entropy Silicon Anodes for Superior Li-Storage Performance of Li-Ion Batteries.

The high-entropy silicon anodes are attractive for enhancing electronic and Li-ionic conductivity while mitigating volume effects for advanced Li-ion batteries (LIBs), but are plagued by the complicated elements screening process. Inspired by the resemblances in the structure between sphalerite and diamond, we have selected sphalerite-structured SiP with metallic conductivity as the parent phase for exploring the element screening of high-entropy silicon-based anodes. The inclusion of the Zn in the sphalerite structure is crucial for improving the structural stability and Li-storage capacity. Within the same group, Li-storage performance is significantly improved with increasing atomic number in the order of BZnSiP3 < AlZnSiP3 < GaZnSiP3 < InZnSiP3. Thus, InZnSiP3-based electrodes achieved a high capacity of 719 mA h g-1 even after 1,500 cycles at 2,000 mA g-1, and a high-rate capacity of 725 mA h g-1 at 10,000 mA g-1, owing to its superior lithium-ion affinity, faster electronic conduction and lithium-ion diffusion, higher Li-storage capacity and reversibility, and mechanical integrity than others. Additionally, the incorporation of elements with larger atomic sizes leads to greater lattice distortion and more defects, further facilitating mass and charge transport. Following these screening rules, high-entropy disordered-cation silicon-based compounds such as GaCuSnInZnSiP6, GaCu(or Sn)InZnSiP5, and CuSnInZnSiP5, as well as high-entropy compounds with mixed-cation and -anion compositions, such as InZnSiPSeTe and InZnSiP2Se(or Te), are synthesized, demonstrating improved Li-storage performance with metallic conductivity. The phase formation mechanism of these compounds is attributed to the negative formation energies arising from elevated entropy.

Element Screening Engineering for High-Entropy Alloy Anodes: Achieving Fast and Robust Li-Storage With Optimal Working Potential.

While the high-entropy strategy is highly effective in enhancing the performance of materials across various fields, an optimal methodology for selecting component elements for performance optimization is still lacking. Here the findings on uncovering the element selection rules for rational design of high-entropy alloy anodes with exceptional lithium storage performance are reported. It is investigated high-entropy element screening rules by modifying stable diamond-structured Ge with P to induce a tetrahedrally coordinated sphalerite structure for enhanced metallic conductivity, further stabilized by incorporating Zn and other elements. Moreover, both theoretical and experimental results confirm that Li-storage performance improves with increasing atomic number: BZnGeP3 < AlZnGeP3 < GaZnGeP3 < InZnGeP3. InZnGeP3-based electrodes demonstrate the highest Li-ion affinity, fastest electronic and Li-ion transport, largest Li-storage capacity and reversibility, and best mechanical integrity. Further element screening based on the above criteria leads to high entropy alloy anodes with metallic conductivity like GaCuSnInZnGeP6, GaCu(or Sn)InZnGeP5, CuSnInZnGeP5, InZnGePSeS(or Te), InZnGeP2S(or Se) which show superior Li-storage performances. The excellent phase stability is attributed to their high configurational entropy. This study offers profound insights into element screening for high-entropy alloy-based anodes in Li-ion batteries, providing guidance and reference for the element combination and screening of other high-entropy functional materials.