The development of renewable energy is one of the most important guarantees to achieve carbon peak and carbon neutrality. However, the instability of solar energy, wind energy and other new energy sources has shown higher requirements on energy characteristic and power characteristic of energy storage devices. This paper firstly discussed the technical characteristics of traditional lithium-ion batteries and supercapacitors, and put forward the necessity of developing battery-capacitors technology under the new grid energy storage requirements. Then, the technical development trend of key materials for battery-capacitors was discussed in detail from three aspects: the improvement of cathode materials, improvement of anode materials, and innovation of electrode sheet structures, current collectors and electrode tabs. Finally, the three key elements of energy storage devices and their “two-in-one” or “three-in-one” effects were proposed to meet the diversified demands of cost, safety, power characteristic and energy characteristic, and the development trend of battery-capacitors was prospected.
