Coordination bonds reinforcing mechanical strength of silicon anode to improve the electrochemical stability

The severe volumetric expansion and poor conductivity of silicon when used as anode in lithium-ion batteries present challenges in maintaining the stability of electrochemical performance. Herein, the binding between silicon nanoparticles and carbon nanotubes (CNTs) is achieved by the utilization of sodium alginate (SA), which is then strengthened by the coordination between Ca²⁺ and the carboxyl group (–COO⁻) of SA, resulting in a stable conductive network with ionic transport pathway. The consolidated binding relationship enables silicon-based anode material to possess high mechanical strength and strong deformation resistance, preventing the separation of silicon from CNTs network. Consequently, this silicon-based anode material demonstrates a discharge specific capacity of 811 mAh·g^–1 after 100 cycles at a current density of 1 A·g^–1, and exhibits high rate performance, with a discharge specific capacity of 1612 mAh·g^–1 at 2 A·g^–1.