Design Double Layered Anode for Stably Introducing Lithium Source to Achieve Sulfur-Carbon Full Batteries

Lithium-sulfur batteries offer high energy density but face great safety and cycle life challenges due to the use of Li metal anode. Replacing the Li metal anode with pre-lithiated carbon anodes can thoroughly address cycling stability and safety issues. Directly contacting Li foil with graphite electrode is one of the most efficient and simple strategy to introduce a high content of lithium source into the sulfur-carbon full batteries. However, the 100% lithiation of the graphite anode through the direct contact method generates excessive heat and stress heterogeneity, which leads to electrode structure cracking and electrochemical properties fading. This study implements a double-layer anode to mitigate these issues. A thin layer of hard carbon placed between graphite and Cu foil limits heat generation and stress heterogeneity due to its structural and electrochemical stability. Additionally, differing from traditional electrochemical lithiation, this method gains better solid electrolyte interphase (SEI) for the graphite anode after several cycles. This research highlights the mass production potential of coupling high energy density lithium source-free cathode materials with various lithium source-free anodes for constructing long-cycle and high-safety rechargeable batteries.