Most of what I've been able to find seems heavily biased, or at least based on European accounts that can be either extremely outlandish or degrading to the people. I understand that many of these are products of their times, largely dealing with the slave trade and coastal voyages, but are there any accounts of explorers that went simply to discover and learn? I also understand (at least from my readings) that these expiditions were largely funded by governments and were in search of something from which they could profit, so taking these things into account is there any reading that could be recommended that is largely unbiased from the original explorations into the interior?
English language that I have read and enjoyed: Anything by Sir Richard Francis Burton Stanley or Livingston Mary Kingsley, botanist, travelled alone; anti missionary, anti chauvinist, anti colonialist; pro native; 2 books
Heinrich Barth's Travels and Discoveries in North and Central Africa is an often interesting read. I'd recommend it alongside Steve Kemper's A Labyrinth of Kingdoms: 10,000 Miles through Islamic Africa, a pretty accessible biography of Barth and summary of his travels (Barth's work is great, but it's also five volumes, so...). Travels and Discoveries has its moments of excitement and adventure, but it was also composed in the interest of discovery and learning—so I think you'll find it pretty rewarding!
(Though in the interest of full disclosure, it's been a long time since I read either Barth or Kemper.)