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Boosting the lifespan of MnO-based materials for future lithium ion batteries is one of the primary challenges due to the intrinsic low ionic conductivity and volume expansion during the conversion process. Herein, superior lithium storage in a new quaternary MnO-Cu-CNT/graphene composite has been demonstrated, which is boosted by pseudocapacitance benefitting from the three-dimensional CNT/graphene and nanosized Cu additives. Such architecture offers highly interpenetrated porous conductive networks in intimate contact with MnO-Cu grains and abundant stress buffer space for effective charge transport upon cycling. The ternary MnO-Cu-graphene electrode contributes an ever-increasing reversible capacity of 938.3 mA h g-1 after 800 cycles at 0.8 A g-1. In particular, the quaternary MnO-Cu-CNT/graphene electrode demonstrates a high specific capacity of 1334 mA h g-1 at 0.8 A g-1 after 800 cycles and long lifetimes of more than 3500 cycles at 5 A g-1 with a capacity of 557.9 mA h g-1 and close-to-100% Coulombic efficiency. The boosted pseudocapacitive lithium storage together with the simple material fabrication method in a MnO-Cu-CNT/graphene hybrid could pave the way for the development of high-capacity and long-life energy storage devices.

Improving the conductivity and charge transfer kinetics is favourable for innovation of sustainable energy devices such as metal oxide/sulfide-based electrodes. Herein, with an intercalation pseudocapacitance effect, an in situ polymerization-carbonization process for novel carbon-sealed vertical MoS2-SnO2 anchored on graphene aerogel (C@MoS2-SnO2@Gr) has enabled excellent rate performance and durability of the anode of lithium ion batteries to be achieved. The integrated carbon layer and graphene matrix provide a bicontinuous conductive network for efficient electron/ion diffusion pathways. The charge transfer kinetics could be enhanced by the synergistic effects between vertical MoS2 nanosheets and well-dispersed SnO2 particles. Based on the crystal surface matching, the ameliorated electric contact between MoS2 and SnO2 can promote the extraction of Li+ from Li2O and restrain the serious aggregation of LixSn. As a result, the improved reversibility leads to a higher initial coulombic efficiency (ICE) of 80% (0.1 A g-1 current density) compared to that of other materials. In particular, with the dominating surface capacitive process, the C@MoS2-SnO2@Gr electrode delivers a stable capacity of 680 mA h g-1 at 2.5 A g-1 for 2000 cycles. Quantitative insight into the origin of the boosted kinetics demonstrated the high pseudocapacitance contribution (above 90%) which leads to the durable high rate Li ion storage.

To accommodate huge volume change and boost the inferior electrochemical reaction kinetics of manganous oxide anodes for lithium-ion batteries, a unique 3D porous CNT/graphene-MnO architecture has been synthesized, with MnO nanoparticles homogeneously decorated on 3D interconnected CNT/graphene (3DCG) conductive networks. This porous 3DCG matrix with its abundant open pores and large surface area can provide efficient channels for fast charge transport and allow full contact between the electrode and electrolyte, leading to improved electrochemical activity. The robust 3D architecture offers abundant stress buffer space to tolerate volume expansion and ensures robust structural stability during the electrochemical processes. The synergistic effect between components endows the 3DCG/MnO electrodes with excellent electrochemical performance, retaining a high specific capacity of 526.7 mA h g-1 at 2.0 A g-1 with 98% capacity retention over 1400 cycles. This work provides a promising route for the practical application of fast and durable lithium-ion batteries and suggests insights for rational structural designs with other transition metal oxides.

Improving the conductivity and charge transfer kinetics is favourable for innovation of sustainable energy devices such as metal oxide/sulfide-based electrodes. Herein, with an intercalation pseudocapacitance effect, an in situ polymerization-carbonization process for novel carbon-sealed vertical MoS