Along with the continuous consumption in lithium-ion batteries (LIBs), the price of cobalt is inevitably going up in recent years. Therefore, recycling valuable Co element from spent devices, and boosting its service ...Along with the continuous consumption in lithium-ion batteries (LIBs), the price of cobalt is inevitably going up in recent years. Therefore, recycling valuable Co element from spent devices, and boosting its service efficiency are becoming two indispensable approaches to promote the utilization of Co in various energy conversion/storage devices. Herein, we realize the recovery of Co from spent LIBs and synthesize a three–dimensional (3D) sea-urchin-like cobalt nitride composite material (labeled as CoN-Gr-2), which is used as a bi-functional catalyst for water splitting. Benefiting from the intrinsic high conductivity, larger surface area and unique 3D sea–urchin–like architecture, CoN-Gr-2 shows an excellent electron transfer efficiency, highly exposed active sites as well as the superior mass transport capacity. The CoN-Gr-2 catalyst exhibits low overpotentials of 128.9 mV and 280 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), which are comparable to the commercial 20 wt% Pt/C and RuO_(2) catalysts. Moreover, when adopting CoN-Gr-2 as both anode and cathode materials for overall water splitting (in 1.0 M KOH electrolyte), the assembled cell achieves a current density of 10 mA cm^(−2) at 1.61 V, which almost close to that of Pt/C||RuO_(2) benchmark (1.60 V), demonstrating its superior water-splitting efficiency. Meanwhile, the CoN catalysts exhibit strong chemical interaction with the Gr support, suppressing the aggregation of CoN catalysts and maintains their high activity during HER and OER reactions. So, the cell exhibits a high current retention of 97.3% after 40 h. This work successfully develops an industrial chain from recycling Co wastes in spent energy devices to controllably designing 3D sea-urchin-like CoN-Gr with high water splitting efficiency. Therefore, it could further promote the efficient utilization of valuable Co element in various energy devices.展开更多
基金The authors would like to acknowledge financial support provided by the Key National Natural Science Foundation of Yunnan Province(No.2018FA028,NO.2019FD039 and No.2019FY003023)the National Natural Science Foundation of China(No.51474191,No.52064049 and No.21467030)+4 种基金the National Natural Science Foundation of Yunnan Provincial Department of Education(No.2020 J0016)the International Joint Research Center for Advanced Energy Materials of Yunnan Province(202003AE140001)the Key Laboratory of Solid State Ions for Green Energy of Yunnan University(2019)the Postdoctoral Foundation of Department of Human Resources and Social Security of Yunnan Province(No.W8163007)the Program for Outstand Young Talents(2018)of Yunnan University.
文摘Along with the continuous consumption in lithium-ion batteries (LIBs), the price of cobalt is inevitably going up in recent years. Therefore, recycling valuable Co element from spent devices, and boosting its service efficiency are becoming two indispensable approaches to promote the utilization of Co in various energy conversion/storage devices. Herein, we realize the recovery of Co from spent LIBs and synthesize a three–dimensional (3D) sea-urchin-like cobalt nitride composite material (labeled as CoN-Gr-2), which is used as a bi-functional catalyst for water splitting. Benefiting from the intrinsic high conductivity, larger surface area and unique 3D sea–urchin–like architecture, CoN-Gr-2 shows an excellent electron transfer efficiency, highly exposed active sites as well as the superior mass transport capacity. The CoN-Gr-2 catalyst exhibits low overpotentials of 128.9 mV and 280 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), which are comparable to the commercial 20 wt% Pt/C and RuO_(2) catalysts. Moreover, when adopting CoN-Gr-2 as both anode and cathode materials for overall water splitting (in 1.0 M KOH electrolyte), the assembled cell achieves a current density of 10 mA cm^(−2) at 1.61 V, which almost close to that of Pt/C||RuO_(2) benchmark (1.60 V), demonstrating its superior water-splitting efficiency. Meanwhile, the CoN catalysts exhibit strong chemical interaction with the Gr support, suppressing the aggregation of CoN catalysts and maintains their high activity during HER and OER reactions. So, the cell exhibits a high current retention of 97.3% after 40 h. This work successfully develops an industrial chain from recycling Co wastes in spent energy devices to controllably designing 3D sea-urchin-like CoN-Gr with high water splitting efficiency. Therefore, it could further promote the efficient utilization of valuable Co element in various energy devices.
