Physics

Solvation

Electrode

Organic chemistry

Biology

Dissolution

Anode

Engineering

Physical chemistry

Power (physics)

Chemistry

Metallurgy

Materials science

Cathode

Sodium

Battery (electricity)

Electrolyte

Interphase

Chemical engineering

Genetics

Thermodynamics

Nature Energy

Sodium-ion batteries (NIBs) have attracted worldwide attention for next-generation energy storage systems. However, the severe instability of the solid–electrolyte interphase (SEI) formed during repeated cycling hinders the development of NIBs. In particular, the SEI dissolution in NIBs with a high-voltage cathode is more severe than in the case of Li-ion batteries (LIBs) and leads to continuous side reactions, electrolyte depletion and irreversible capacity loss, making NIBs less stable than LIBs. Here we report a rational electrolyte design to suppress the SEI dissolution and enhance NIB performance. Our electrolyte lowers the solvation ability for SEI components and facilitates the formation of insoluble SEI components, which minimizes the SEI dissolution. In addition to the stable SEI on a hard carbon (HC) anode, we also show a stable interphase formation on a NaNi0.68Mn0.22Co0.1O2 (NaNMC) cathode. Our HC||NaNMC full cell with this electrolyte demonstrates &gt;90% capacity retention after 300 cycles when charged to 4.2 V. This study enables high-voltage NIBs with long cycling performance and provides a guiding principle in electrolyte design for sodium-ion batteries. The dissolution of the solid–electrolyte interphase formed during repeated cycling severely deteriorates the performance of sodium-ion batteries. Here the authors develop an electrolyte that effectively suppresses the dissolution and consequently enables a long-cycle and high-voltage sodium-ion battery.

Low-solvation electrolytes for high-voltage sodium-ion batteries