A surface-controlled process renders high-power Li-ion storage in Mn3O4/RGO composites for both lithium-ion capacitors and batteries.

Lack of high-performance active materials limits the rapid development of advanced energy storage devices with both high power and high-energy performance. Here, Mn3O4/reduced graphene oxide (RGO) was synthesized as a negative material for both lithium-ion batteries (LIBs) and lithium-ion capacitors (LICs). The RGO prevents the aggregation of Mn3O4 and enhances the charge transport rate, enabling Mn3O4/RGO to exhibit high specific capacity, superior rate performance, and long cycling stability. More significantly, the charge storage of Mn3O4/RGO is mainly from the surface controlled reaction, which accounts for 58.2–83.3% of charge storage capacity when the scan rate increases from 0.1 to 1.0 mV s−1. Owing to high specific capacity and fast reaction kinetics of Mn3O4/RGO, the composite exhibits high energy performance when assembled with a LiNi0.5Co0.2Mn0.3O2 cathode, and achieves both high-energy and high-power performance in LICs after being assembled with activated carbon (AC). The LiNi0.5Co0.2Mn0.3O2//Mn3O4/RGO LIB displays a specific energy of 144.8 W h kg−1 at 215.1 W kg−1, and the AC//Mn3O4/RGO LIC exhibits a specific energy of 98.6 W h kg−1 at 180.1 W kg−1 with a retained specific energy of 70.3 W h kg−1 at a high specific power of 1937.5 W kg−1. [ABSTRACT FROM AUTHOR]