# The Progress of Cobalt-Based Anode Materials for Lithium Ion Batteries and Sodium Ion Batteries
## 5 Conclusions and Perspectives  
The increasing consumption of fossil energy makes the development of clean energy necessary. Due to time and geographical constraints, high-performance RBs are urgent for the development of clean energy. Designing and synthesizing suitable electrode materials is critical for the development of RBs. This review systematically demonstrates that cobalt-based electrode materials are expected to be a new generation of anode materials for LIBs/SIBs. In this review, we sequentially summarized the Li\({}^{+}\)/Na\({}^{+}\) storage mechanism, typical preparation methods and applications of various cobalt-based anode materials, including cobalt-based alloy, cobalt oxide, cobalt sulfides and cobalt phosphides. For cobalt-based anode materials, their large volume changes and poor conductivity during charges and discharges are the main obstacles to the further development in LIBs/SIBs. In this regard, future research can focus on the following aspects:  
1. Developing a simple and feasible synthetic process for the preparation of cobalt-based anode materials with specific morphology and sizes, which can ensure satisfactory contact between the electrolyte and active material, and cycle performances of cobalt-based anode materials. In addition, the combination with the conductive material can improve the conductivity of the electrode material and improve the rate performances of the cobalt-based anode materials. 2. More advanced characterization and calculation methods should be used to further study the Li\({}^{+}\)/Na\({}^{+}\) storage mechanisms of cobalt-based anode materials, which will be meaningful for designing a suitable morphology. 3. Considering commercial applications, the whole battery system, including cathode materials, binders, conductive agents, electrolytes and additives, should also be optimized. Appropriate matching materials can fully exploit the advantages of the high storage capacities of cobalt-based anode materials in LIBs/SIBs. [PERSON] and [PERSON] wrote the manuscript. [PERSON] revised the manuscript. All authors commented on the manuscript and have contributed equally to this work. All authors have read and agreed to the published version of the manuscript. This work was supported by the Australian Research Council (ARC; DE200101384) for the support provided through a Discovery Project (DP160102627) and a Linkage Project (LP160100273) and the Shanxi Province Science Foundation for Youths (No. 201901D211257). We acknowledge the support from Australian Research Council for the support provided through a Discovery Project and a Linkage Project and the Shanxi Province Science Foundation for Youths. The authors declare no conflict of interest. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Types of Materials** & \begin{tabular}{c} **Current Density** \\ **(A g\({}^{-1}\))** \\ \end{tabular} & \begin{tabular}{c} **Cut-off** \\ **Voltage (V)** \\ \end{tabular} & \
\begin{tabular}{c} **Cycle** \\ **Number** \\ \end{tabular} &
\begin{tabular}{c} **Specific Capacity** \\ **(mA h g\({}^{-1}\))** \\ \end{tabular} & **Reference** \\ \hline CoS\({}_{2}\)-MWCNT & 0.1 & 1–2.9 & 100 & 568 & [47] \\ cs\(<\)Co\({}_{5}\)/DPC & 0.5 & 0.01–3 & 50 & 300 & [181] \\ CoS\({}_{2}\)/fGO & 1 & 0.01–3 & 1000 & 192 & [49] \\ CoSeGCO & 1 & 0.1–2.9 & 1000 & 420 & [173] \\ (CoS\({}_{8}\) SD@HCP)@FOO & 0.3 & 0.01–2.9 & 500 & 628 & [172] \\ CoS@FOO & 1 & 0.01–2.9 & 1000 & 420 & [173] \\ CoS\({}_{8}\)@NSC & 1 & 0.01–3 & 200 & 606 & [186] \\ CoS\({}_{8}\)@C & 5 & 0.01–3 & 1000 & 305 & [23] \\ Urchin-like CoSe\({}_{2}\) & 1 & 0.5–3 & 1800 & 410 & [190] \\ CoSe@PCP & 0.1 & 0.005-3 & 100 & 341 & [68] \\ CoSe\({}_{2}\) nanorods & 5 & 0.4–3 & 2000 & 386 & [168] \\ CoSe\({}_{2}\)@N-PGC/CNTs & 0.2 & 0.001–3 & 100 & 424 & [48] \\ CoSe\({}_{8}\)/rGO & 0.05 & 0.01–3 & 100 & 406 & [97] \\ CoSe/C & 0.5 & 0.01–3 & 50 & 552.5 & [166] \\ CoSe@100 CSs & 4 & 0.5–2.8 & 10,000 & 260 & [60] \\ CoSe\({}_{2}\)/N-CNF & 2 & 0.5–3 & 1000 & 308.4 & [24] \\ \hline \hline \end{tabular}
\end{table} 
Table 3: _Cont._