A review of current collectors for lithium-ion batteries

Lithium-ion batteries are the state-of-the-art power source for most consumer electronic devices. Current collectors are indispensable components bridging lithium-ion batteries and external circuits, greatly influencing the capacity, rate capability and long-term stability of lithium-ion batteries. Conventional current collectors, Al and Cu foils have been used since the first commercial lithium-ion battery, and over the past two decades, the thickness of these current collectors has decreased in order to increase the energy density . However to improve the performance further, alternative materials and structures, as well as specific treatments such as etching and carbon coating, have also been investigated to enhance the electrochemical stability and electrical conductivity of current collectors, for next-generation lithium-ion batteries with higher capacities and longer service lifetime. This work reviews six types of materials for current collectors, including Al, Cu, Ni, Ti, stainless steel and carbonaceous materials , and compares these materials from five aspects of electrochemical stability, electrical conductivity , mechanical property, density and sustainability. The effects of three different structures of foil, mesh and foam as well as two treatments of chemical etching and coating are also discussed. Future opportunities are highlighted at the end of this review. • Six different types of current collector materials for batteries are reviewed. • The performance, stability, cost and sustainability are compared. • 2D and 3D structures of foil, mesh and foam are introduced. • Future direction and opportunities for 2D and 3D current collectors are provided.