Carefully designed solid-electrolyte interphases are required for stable, reversible and efficient electrochemical energy storage in batteries. We report that hybrid battery anodes created by depositing an electrochemically active metal (for example, Sn, In or Si) on a reactive alkali metal electrode by a facile ion-exchange chemistry lead to very high exchange currents and stable long-term performance of electrochemical cells based on Li and Na electrodes. By means of direct visualization and ex situ electrodeposition studies, Sn–Li anodes are shown to be stable at 3 mA cm−2 and 3 mAh cm−2. Prototype full cells in which the hybrid anodes are paired with high-loading LiNi0.8Co0.15Al0.05O2(NCA) cathodes are also reported. As a second demonstration, we create and study Sn–Na hybrid anodes and show that they can be cycled stably for more than 1,700 hours with minimal voltage divergence. Charge storage at the hybrid anodes is reported to involve a combination of alloying and electrodeposition reactions.
This work was supported by the Department of Energy (DOE), Advanced Research Projects Agency - Energy (ARPA-E) through award no. DE-AR0000750. M.J.Z. and L.F.K. acknowledge support by the NSF (DMR-1654596). The work made use of electrochemical characterization facilities in the KAUST-CU Centre for Energy and Sustainability, supported by the King Abdullah University of Science and Technology (KAUST) through award no. KUS-C1-018-02. Electron microscopy facilities at the Cornell Centre for Materials Research (CCMR), an NSF-supported MRSEC through Grant DMR-1120296, were also used for the study. Additional support for the FIB/SEM cryo-stage and transfer system was provided by the Kavli Institute at Cornell and the Energy Materials Centre at Cornell, DOE EFRC BES (DE-SC0001086). Z.T. thanks B. Polzin for kindly providing NCA cathode materials from the Cell Analysis, Modeling, and Prototyping (CAMP) Facility at Argonne National Laboratories.