New Insights into the Electrochemistry Superiority of Liquid Na–K Alloy in Metal Batteries

Abstract

The significant issues with alkali metal batteries arise from their poor electrochemical properties and safety problems, limiting their applications. Herein, TiO2 nanoparticles embedded into N‐doped porous carbon truncated ocatahedra (TiO2⊂NPCTO) are engineered as a cathode material with different metal anodes, including solid Na or K and liquid Na–K alloy. Electrochemical performance and kinetics are systematically analyzed, with the aim to determine detailed electrochemistry. By using a galvanostatic intermittent titration technique, TiO2⊂NPCTO/NaK shows faster diffusion of metal ions in insertion and extraction processes than that of Na‐ions and K‐ions in solid Na and K. The lower reaction resistance of liquid Na–K alloy electrode is also examined. The higher b‐value of TiO2⊂NPCTO/NaK confirms that the reaction kinetics are promoted by the surface‐induced capacitive behavior, favorable for high rate performance. This superiority highly pertains to the distinct liquid−liquid junction between the electrolyte and electrode, and the prohibition of metal dendrite growth, substantiated by symmetric cell testing, which provides a robust and homogeneous interface more stable than the traditional solid−liquid one. Hence, the liquid Na–K alloy‐based battery exhibits to better cyclablity with higher capacity, rate capability, and initial coulombic efficiency than solid Na and K batteries.

Mixed alkali-ion transport and storage in atomic-disordered honeycomb layered NaKNi2TeO6

“…These electrochemical measurements indicate that NaKNi 2 TeO 6 mixed-alkali honeycomb layered oxide is amenable to electrochemical binary alkali-ion transport and storage, pointing towards the possibility of developing a viable mixed Na + ‒ and K + ‒ion electrochemical cell that relies on electrolytes and electrode materials that can accommodate both Na + and K + binary-cation transport. Given that cells utilising both cation and anion as charge carriers (dual-ion batteries (DIBs)) have already shown remarkable metrics in terms of energy density, power density and cycling life 37 – 39 , the present battery chemistry exploiting binary alkali metal cations could be a promising successor to DIB technology 38 , 40 – 42 . Indeed, taking into account the abundance of Na and K, a cell with suitable specific energy and cyclability can be designed.…”

Advanced Post‐Potassium‐Ion Batteries as Emerging Potassium‐Based Alternatives for Energy Storage

“…[34,102] Currently, strategies for stabilizing K metal anode can be classified into electrode modifications, electrolyte designs, and interface projects. [103][104][105][106] Furthermore, K metal anode is not only important for PIBs but also a key point for the development of K-S and K-Se batteries along with ASSPIBs as discussed above.…”

Three‐Dimensional Graphene Network Decorated with Highly Symmetrical Cuboid Na3V2(PO4)2F3 Particles: High Rate Capability and Cycling Stability for Sodium‐Ion Batteries

“…D Na + is calculated by the equation originally from Weppner and Huggins as follows [Eq. ]: [34] …”