Lignin-Based Mesoporous Hollow Carbon@MnO2 Nanosphere Composite as an Anodic Material for Lithium-Ion Batteries

Lignin-based carbonaceous materials have been demonstrated to be one of the promising alternatives for the next-generation anodic materials of lithium-ion batteries (LIBs), which was due to their non-toxic, good thermal stability, favorable biodegradability and abundant reserves. However, the lower capacity and shorter cycling life of the lignin-based carbon materials are unable to satisfy the growing demand for long cycling lifespan and high energy density electrode materials of the LIBs. Herein, a lignin-based mesoporous hollow carbon@MnO2 nanosphere composite (L-C-NSs@MnO2) was fabricated by employing the lignosulfonate as the carbon source. The nanostructured MnO2 particles with a diameter of 10~20 nm were uniformly immobilized on the surfaces of the hollow carbon nanospheres. The obtained L-C-NSs@MnO2 nanosphere composite showed prolonged cycling stability and excellent rate capability when used as an anodic material for LIBs. The L-C-NSs@MnO2 nanocomposite, with a MnO2 content of 24.6 wt%, showed a specific discharge capacity of 478 mAh g−1 after 500 discharge/charge cycles, and the capacity contribution of MnO2 in the L-C-NSs@MnO2 nanocomposite was calculated to be 1268.8 mAh g−1, corresponding to 103.2% of the theoretical capacity of MnO2 (1230 mAh g−1). In addition, the capacity degradation rate was ca. 0.026% per cycle after long-term and high-rate Li+ insertion/extraction processes. The three-dimensional lignin-based carbon nanospheres played an important role in buffering the volume change and agglomeration of the MnO2 nanoparticles during the discharge/charge cycles. Furthermore, the large specific surface areas and mesoporous structure properties of the hollow carbon nanospheres significantly contribute to the fast transport of the Li+ and e−, improving both the cycling stability and rate capability of the L-C-NSs@MnO2 electrode materials. The presented work shows that the combination of specific structured lignin-based carbon nanoarchitectures with MnO2 provides a new thought for the designation and preparation of high-performance electrode for energy-related applications.