Synergistic Interface-Mass-Mechanical Modulation of Ge Thin-Film Anode by Functional Carbon Nanobox for Lithium-Ion...

Germanium (Ge) is a promising anode material for lithium-ion batteries (LIBs) owing to its high theoretical capacity and superior electronic conductivity, yet its practical application is severely hindered by drastic volume expansion during cycling. To address this issue, a Ge thin-film anode is deposited onto a pre-synthesized hollow carbon nanobox@Cu (CB@Cu) current collector, which enables synergistic interface-mass transfer-mechanical modulation. The introduced CB interlayer favorably reduces the electron tunneling barrier and optimizes current distribution, enhancing electrode conductivity. The hollow porous carbon architecture ensures sufficient electrolyte penetration and intimate electrode/electrolyte contact, accelerating Li⁺ diffusion kinetics. Meanwhile, the internal void space effectively accommodates volume expansion of Ge, maintaining solid electrolyte interphase (SEI) layer integrity over prolonged cycling. Consequently, the Ge@CB electrode delivers a reversible capacity exceeding 1000 mAh g^-1 and exhibits superior rate capability up to 10 A g^-1, significantly outperforming the Ge electrode without CB modification. Combined experimental and theoretical investigations elucidate the synergistic mechanism, demonstrating an effective strategy for high-performance thin-film anodes.