Self‐Formulated Na‐Based Dual‐Ion Battery Using Nonflammable SO₂‐Based Inorganic Liquid Electrolyte

Abstract

Sodium secondary batteries have gained much attention as alternative power sources to replace lithium secondary batteries. However, some technical issues must be solved to ensure their success. Here, a highly safe and cost‐effective Na‐based dual‐ion battery system employing self‐formulated CuCl cathode material starting from a mixture of Cu and NaCl in conjunction with a nonflammable NaAlCl4·2SO2 inorganic liquid electrolyte is demonstrated. It is found that CuCl is spontaneously formed by redox coupling of Cu/Cu(I) and SO2/SO2− anion radical. In the proposed battery, Na+ and Cl− are employed as energy carriers for the anode and cathode, respectively, and it is further demonstrated that the Na‐metal‐free battery configuration is possible using a hard carbon anode. Owing to the use of cheap electrode materials and a highly conductive and safe electrolyte, the proposed batteries deserve to be regarded as a promising approach for next‐generation Na rechargeable batteries.

Fundamental Understanding and Optimization Strategies for Dual-Ion Batteries: A Review

“…As a result, the effects of separate electrolyte components (salts, solvents, and additives), their oxidation/reduction at the cathode/anode sides, the “solvation effects” of anions, the formation and instability of SEI layer, the co-intercalation of solvent molecules into cathode materials are key issues to be addressed [ 93 ]. Besides, the cost and safety are also need to be considered, thus calling for more requirements apart from the characteristics of LIBs electrolyte systems [ 94 ]. The past decade has seen tremendous growth in the design and preparation of DIBs electrolytes with varying optimization strategies, including quasi-solid-state electrolytes (QSSEs), high-concentration electrolytes, high-voltage electrolytes, and the exploitation of electrolyte additives tailored for DIBs [ 95 - 97 ].…”

Reversible flowering of CuO nanoclusters via conversion reaction for dual-ion Li metal batteries

“…To address this issue, Kwak et al, Kim et al, and Li et al used copper metal and copper oxides as cathode materials, which were converted to CuCl or CuCl 2 through a self-activation process before the initial charging or discharging began [ 9 – 11 ]. However, the self-activation process leads to a large volume expansion of the cathode (e.g., conversion of CuO to CuCl 2 is accompanied by 224% volume expansion), which is responsible for the low initial capacity and degraded cycle retention of copper metal or copper oxide cathodes [ 10 , 11 ].…”

High Discharge Capacity and Ultra-Fast-Charging Sodium Dual-Ion Battery Based on Insoluble Organic Polymer Anode and Concentrated Electrolyte

“…Currently, the anodes of SDIBs are mainly based on inorganic materials, such as hard carbon, , alloy compounds, , transition metal oxides, , and Prussian blue analogues. , Nevertheless, these materials commonly exhibit poor cyclability, low specific discharge capacity (SDC), and initial Coulomb efficiency (ICE) and more importantly do not conform to the “green battery” development concept . The challenge for green and sustainable SDIB technology is the exploitation of renewable organic anodes, which may eventually be synthesized from biomass. , …”