Silicon is a low price and high capacity anode material for lithium-ion batteries. The yolk-shell structure can effectively accommodate Si expansion to improve stability. However, the limited rate performance of Si anodes can’t meet people’s growing demand for high power density. Herein, the phosphorus-doped yolk-shell Si@C materials (P-doped Si@C) were prepared through carbon coating on P-doped Si/SiOx matrix to obtain high power and stable devices. Therefore, the as-prepared P-doped Si@C electrodes delivered a rapid increase in Coulombic efficiency from 74.4% to 99.6% after only 6 cycles, high capacity retention of ∼ 95% over 800 cycles at 4 A·g−1, and great rate capability (510 mAh·g−1 at 35 A·g−1). As a result, P-doped Si@C anodes paired with commercial activated carbon and LiFePO4 cathode to assemble lithium-ion capacitor (high power density of ∼ 61,080 W·kg−1 at 20 A·g−1) and lithium-ion full cell (good rate performance with 68.3 mAh·g−1 at 5 C), respectively. This work can provide an effective way to further improve power density and stability for energy storage devices.

The NaTi2(PO4)3 (NTP) anode materials exhibit high Na+ diffusion dynamics; carbon-based materials can effectively improve its limited electronic conductivity. However, the low Na+ diffusion of NTP/C composite materials from inhomogeneous carbon mixing or uncontrollable carbon coating cannot keep up with fast electron transfer, leading to undesirable electrochemical performances. Herein, a uniform and controllable carbon layer is designed on the self-supported-coated NTP nanorod arrays with binder-free (NTP@C NR) to improve Na+ and electron kinetics simultaneously. As a result, the NTP@C NR electrodes possess initial coulombic efficiency (ICE = 97%), good rate capabilities (89.1 mA h g–1 at 100 C), and stability with ≈78.4% of capacity retention rate at even 30 C over 1200 cycles. The sodium-ion capacitors with NTP@C NR as an anode and commercially activated carbon as a cathode exhibit ∼9180.0 W kg–1 of power density at 10 A g–1 and super high retention of ≈94.5% at 1 A g–1 over 7000 cycles. This work will help balance transport kinetics between the ion and electron for materials applied in storage devices.

As conversion material, ZnMn 2 O 4 has a high theoretical specific capacity as an anode for Lithium-ion batteries. This paper has designed a facile method to prepare urchin-like ZnMn 2 O 4 architectures with high quality and well crystallinity. The resultant urchin-like ZnMn 2 O 4 architectures exhibit high discharge capacity and excellent cycling stability. The initial discharge capacity of urchin-like ZnMn 2 O 4 architectures is 1167 mAh g À 1 at 0.4 A g À 1 and the electrode materials could maintain high reversible capacity of 889 mAh g À 1 after 150 cycles. Even in the high current density of 1 A g À 1 , the electrode of urchin-like ZnMn 2 O 4 can keep a high reversible capacity of 578 mAh g À 1 after 300 cycles. The improved electrochemical performance can be ascribed to the urchin-like architectures of the as-prepared ZnMn 2 O 4 , which could be conducive to the transmission of lithium ions and electrons and provide sufficient void spaces to tolerate the volume change during the Li + intercalation. These results revealed that as-prepared urchin-like ZnMn 2 O 4 architectures would be a promising anode for high performance Lithium-ion batteries.

No abstract