Design and electrochemical investigation of a novel graphene oxide-silver joint conductive agent on LiFePO4 cathodes in rechargeable lithium-ion batteries

Improvement of Lithium Storage Performance of Silica Anode by Using Ketjen Black as Functional Conductive Agent

In this paper, SiO₂ aerogels were prepared by a sol–gel method. Using Ketjen Black (KB), Super P (SP) and Acetylene Black (AB) as a conductive agent, respectively, the effects of the structure and morphology of the three conductive agents on the electrochemical performance of SiO₂ gel anode were systematically investigated and compared. The results show that KB provides far better cycling and rate performance than SP and AB for SiO₂ anode electrodes, with a reversible specific capacity of 351.4 mA h g⁻¹ at 0.2 A g⁻¹ after 200 cycles and a stable 311.7 mA h g⁻¹ at 1.0 A g⁻¹ after 500 cycles. The enhanced mechanism of the lithium storage performance of SiO₂-KB anode was also proposed.

Effect of Conductive Material Morphology on Spherical Lithium Iron Phosphate

As an integral part of a lithium-ion battery, carbonaceous conductive agents have an important impact on the performance of the battery. Carbon sources (e.g., granular Super-P and KS-15, linear carbon nanotube, layered graphene) with different morphologies were added into the battery as conductive agents, and the effects of their morphologies on the electrochemical performance and processability of spherical lithium iron phosphate were investigated. The results show that the linear carbon nanotube and layered graphene enable conductive agents to efficiently connect to the cathode materials, which contribute to improving the stability of the electrode-slurry and reducing the internal resistance of cells. The batteries using nanotubes and graphene as conductive agents showed weaker battery internal resistance, excellent electrochemical performance and low-temperature dischargeability. The battery using carbon nanotube as the conductive agent had the best overall performance with an internal resistance of 30 mΩ. The battery using a carbon nanotube as the conductive agent exhibited better low-temperature performance, whose discharge capacity at -20 °C can reach 343 mAh, corresponding to 65.0% of that at 25 °C.

Improved Electrochemical Performance of LiFePO4@N-Doped Carbon Nanocomposites Using Polybenzoxazine as Nitrogen and Carbon Sources

Polybenzoxazine is used as a novel carbon and nitrogen source for coating LiFePO₄ to obtain LiFePO₄@nitrogen-doped carbon (LFP@NC) nanocomposites. The nitrogen-doped graphene-like carbon that is in situ coated on nanometer-sized LiFePO₄ particles can effectively enhance the electrical conductivity and provide fast Li⁺ transport paths. When used as a cathode material for lithium-ion batteries, the LFP@NC nanocomposite (88.4 wt % of LiFePO₄) exhibits a favorable rate performance and stable cycling performance.