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

Abstract

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 LiNi_0.5Co_0.2Mn_0.3O₂ cathode, and achieves both high-energy and high-power performance in LICs after being assembled with activated carbon (AC). The LiNi_0.5Co_0.2Mn_0.3O₂//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.