Enabling Natural Graphite in High‐Voltage Aqueous Graphite || Zn Metal Dual‐Ion Batteries. Issue 41 (28th September 2020) - Rodríguez‐Pérez, Ismael A.
Abstract: Safety and cost are the key metrics for large‐scale energy storage. Due to the use of nonaqueous electrolytes and transition metal oxides in current lithium‐ion battery technologies, safety, cost, and environmental issues are a significant cause for concern. Graphite is a promising cathode material for dual‐ion batteries due to its high operating potential, low cost, and high safety. Nevertheless, it is challenging to find a suitable aqueous electrolyte due to the narrow electrochemical stability window (1.23 V). This work presents a graphite || zinc metal aqueous dual‐ion battery of ≈2.3–2.5 V, a remarkably high voltage in aqueous zinc batteries, achieving >80% capacity retention after 200 cycles and delivering ≈110 mAh g –1 at a charge/discharge current of 200 mA g –1 . A capacity of nearly 60 mAh g –1 is achieved at a charge/discharge current of 5000 mA g –1 . Natural graphite is enabled as a reversible cathode using a highly concentrated lithium‐free bisalt aqueous electrolyte. Abstract : In this work, a practical aqueous graphite || Zn dual‐ion battery for grid storage is demonstrated with a high‐voltage operation, supported by fundamental insights into the storage mechanism via electrochemical characterization, advanced structural characterization, and theory.