Putting Nanoarmors on Yolk–Shell Si@C Nanoparticles: A Reliable Engineering Way To Build Better Si-Based Anodes for Li-Ion Batteries

Practical utilization of silicon (Si) for Li-ion batteries (LIBs) still remains sluggish because of its formidable kinetic problems of huge volume expansions over 300%, instable solid electrolyte interphase (SEI), and unsatisfactory electrical conductivity. Though using a yolk–shell (Y–S) Si@C nanodesign indeed helps to mitigate active changes, optimize SEI properties, and lower intrinsic charge-transfer impedances, the total anodic behaviors in reversibility, rate capabilities, and long-lasting cyclability are still far from perfect. To settle the above issues, we herein propose a reliable and effective way by putting tough and malleable Ni nanoarmors on Y–S Si@C nanoparticles (Si@C⊆Ni). The unique functionalized configurations endow such hybrid systems with superb reversible capacity retention (almost no capacity decay emerges in 600 cycles, retaining a reversible capacity beyond ∼1307 mA h g–1), prominent cyclic stability, and rate behaviors. To justify their potential usage, full cells of (−)­Si@C⊆Ni//LiFePO4(+) are further constructed, delivering impressive specific energy and power densities (max. values: ∼423 W h kg–1/∼497.8 W kg–1). This paradigm work may offer a highly feasible engineering protocol to push forward Si anode performances for next-generation LIBs.