Mechanical prelithiation of Sn/C@ZrO2 yolk-shell anode for full cell cycling

Tin anode is a great hope in lithium-ion batteries for its encouragingly high theoretical capacity. However, the huge capacity fading and short cycle life of pure Sn powder anode always fail to live up to our expectations. Currently, the huge volume expansion (-300%) is acknowledged as the chief culprit to the pulverization of pure Sn, which deteriorates severely the cycle performance. Coating an artificial layer on Sn particles followed by preconstructing a void space is generally thought a savior to this generic problem of alloying anodes besides Sn. Although with the aid of interspace to accommodate volume expansion, a higher Coulombic efficiency as well as improved capacity retention is achieved in half-cell test where more than enough lithium inventory is supplied, the performance is usually quite poor when it comes to a well-matched full cell. Careful examination reveals the fact that too much lithium has been consumed in parasitic reactions before reaching a stable cycling is attributed to such a frustrating dilemma, making prelithiation critical for real applications of tin anode materials. Herein, we prepared Sn/C@ZrO2 yolk-shell structure and then its electrochemical performance is examined. This newly developed anode material delivered a high initial Coulombic efficiency of 80.92% and an outstanding cycle stability presented with 800 cycles in half-cell, far more superior than the pure Sn anode which suffered a striking capacity loss of 90% within merely 200 cycles. More significantly, a mechanical prelithiation method for slurrycasting anodes was introduced in this paper. After this strategy was applied in Sn/C@ZrO2 anode, the prelithiated anode showed a favorable full-cell performance when matched against LFP cathode. The initial Coulombic efficiency reached 90.25%, and the Coulombic efficiency could achieve 99% from the 3rd cycle. The encouraging improvement of cycle performance and specific capacity will greatly help researchers regain the confidence on coated Sn anode for high-performance lithium-ion full cells.

Automated summary

Pure tin anode in lithium-ion batteries suffers from capacity fading and short cycle life due to huge volume expansion, which can be improved by coating and preconstructing void space. Introducing a mechanical prelithiation method significantly enhances the performance of prelithiated Sn/C@ZrO2 anode, achieving higher Coulombic efficiency and improved cycle stability in full-cell testing. This encouraging improvement demonstrates the potential of coated tin anode for high-performance lithium-ion full cells.